diff --git a/.evergreen/config_generator/components/sanitizers.py b/.evergreen/config_generator/components/sanitizers.py
index 5afa5a7e6f..1f1057cbef 100644
--- a/.evergreen/config_generator/components/sanitizers.py
+++ b/.evergreen/config_generator/components/sanitizers.py
@@ -22,8 +22,7 @@
 # pylint: disable=line-too-long
 # fmt: off
 MATRIX = [
-    ('rhel80', ['asan',        ], ['shared', 'static'], [False, True], ['4.0', '8.0', 'latest'], ['single', 'replica', 'sharded']),
-    ('rhel80', [        'ubsan'], [          'static'], [False      ], ['4.0', '8.0', 'latest'], ['single', 'replica', 'sharded']),
+    ('rhel80', ['asan', 'ubsan'], ['shared', 'static'], [False, True], ['4.0', '8.0', 'latest'], ['single', 'replica', 'sharded']),
 ]
 # fmt: on
 # pylint: enable=line-too-long
@@ -101,7 +100,7 @@ def tasks():
                     test_vars |= {
                         'TEST_WITH_UBSAN': 'ON',
                         'example_projects_cxxflags': '-fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer',
-                        'example_projects_ldflags': '-fsanitize=undefined -fno-sanitize-recover=undefined',
+                        'example_projects_ldflags': '-fsanitize=undefined -fno-sanitize-recover=undefined' + (' -static-libsan' if link_type == 'static' else ''),
                     }
 
             commands += [
diff --git a/.evergreen/generated_configs/tasks.yml b/.evergreen/generated_configs/tasks.yml
index 067b980a93..34c63de528 100644
--- a/.evergreen/generated_configs/tasks.yml
+++ b/.evergreen/generated_configs/tasks.yml
@@ -15947,9 +15947,728 @@ tasks:
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=address -fno-omit-frame-pointer
           example_projects_ldflags: -fsanitize=address
+  - name: sanitizers-ubsan-rhel80-clang-shared-4.0-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, "4.0", replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-4.0-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, "4.0", sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-4.0-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, "4.0", single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-8.0-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, "8.0", replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: "8.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-8.0-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, "8.0", sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: "8.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-8.0-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, "8.0", single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: "8.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-4.0-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, "4.0", replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-4.0-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, "4.0", sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-4.0-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, "4.0", single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-8.0-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, "8.0", replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: "8.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-8.0-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, "8.0", sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: "8.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-8.0-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, "8.0", single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: "8.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-latest-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, latest, replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-latest-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, latest, sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-extra_alignment-latest-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, extra_alignment, latest, single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-latest-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, latest, replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-latest-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, latest, sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+  - name: sanitizers-ubsan-rhel80-clang-shared-latest-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, shared, latest, single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
   - name: sanitizers-ubsan-rhel80-clang-static-4.0-replica
     run_on: rhel80-large
-    tags: [sanitizers, ubsan, rhel80, clang, static, "4.0", replica]
+    tags: [sanitizers, ubsan, rhel80, clang, static, "4.0", replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-4.0-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, "4.0", sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-4.0-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, "4.0", single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          ENABLE_TESTS: "ON"
+          RUN_DISTCHECK: 1
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-8.0-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, "8.0", replica]
     commands:
       - command: expansions.update
         params:
@@ -15962,7 +16681,7 @@ tasks:
       - func: start_mongod
         vars:
           TOPOLOGY: replica_set
-          mongodb_version: "4.0"
+          mongodb_version: "8.0"
       - func: install_c_driver
         vars:
           SKIP_INSTALL_LIBMONGOCRYPT: 1
@@ -15981,10 +16700,10 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
-  - name: sanitizers-ubsan-rhel80-clang-static-4.0-sharded
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-8.0-sharded
     run_on: rhel80-large
-    tags: [sanitizers, ubsan, rhel80, clang, static, "4.0", sharded]
+    tags: [sanitizers, ubsan, rhel80, clang, static, "8.0", sharded]
     commands:
       - command: expansions.update
         params:
@@ -15997,7 +16716,7 @@ tasks:
       - func: start_mongod
         vars:
           TOPOLOGY: sharded_cluster
-          mongodb_version: "4.0"
+          mongodb_version: "8.0"
       - func: install_c_driver
         vars:
           SKIP_INSTALL_LIBMONGOCRYPT: 1
@@ -16016,10 +16735,10 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
-  - name: sanitizers-ubsan-rhel80-clang-static-4.0-single
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-8.0-single
     run_on: rhel80-large
-    tags: [sanitizers, ubsan, rhel80, clang, static, "4.0", single]
+    tags: [sanitizers, ubsan, rhel80, clang, static, "8.0", single]
     commands:
       - command: expansions.update
         params:
@@ -16031,7 +16750,7 @@ tasks:
       - func: setup
       - func: start_mongod
         vars:
-          mongodb_version: "4.0"
+          mongodb_version: "8.0"
       - func: install_c_driver
         vars:
           SKIP_INSTALL_LIBMONGOCRYPT: 1
@@ -16050,10 +16769,117 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
-  - name: sanitizers-ubsan-rhel80-clang-static-8.0-replica
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-4.0-replica
     run_on: rhel80-large
-    tags: [sanitizers, ubsan, rhel80, clang, static, "8.0", replica]
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, "4.0", replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-4.0-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, "4.0", sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-4.0-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, "4.0", single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: "4.0"
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-8.0-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, "8.0", replica]
     commands:
       - command: expansions.update
         params:
@@ -16069,12 +16895,13 @@ tasks:
           mongodb_version: "8.0"
       - func: install_c_driver
         vars:
+          BSON_EXTRA_ALIGNMENT: 1
           SKIP_INSTALL_LIBMONGOCRYPT: 1
       - func: install-uv
       - func: compile
         vars:
+          BSON_EXTRA_ALIGNMENT: 1
           ENABLE_TESTS: "ON"
-          RUN_DISTCHECK: 1
           USE_SANITIZER_UBSAN: "ON"
       - func: fetch-det
       - func: run_kms_servers
@@ -16085,10 +16912,10 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
-  - name: sanitizers-ubsan-rhel80-clang-static-8.0-sharded
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-8.0-sharded
     run_on: rhel80-large
-    tags: [sanitizers, ubsan, rhel80, clang, static, "8.0", sharded]
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, "8.0", sharded]
     commands:
       - command: expansions.update
         params:
@@ -16104,12 +16931,13 @@ tasks:
           mongodb_version: "8.0"
       - func: install_c_driver
         vars:
+          BSON_EXTRA_ALIGNMENT: 1
           SKIP_INSTALL_LIBMONGOCRYPT: 1
       - func: install-uv
       - func: compile
         vars:
+          BSON_EXTRA_ALIGNMENT: 1
           ENABLE_TESTS: "ON"
-          RUN_DISTCHECK: 1
           USE_SANITIZER_UBSAN: "ON"
       - func: fetch-det
       - func: run_kms_servers
@@ -16120,10 +16948,10 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
-  - name: sanitizers-ubsan-rhel80-clang-static-8.0-single
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-8.0-single
     run_on: rhel80-large
-    tags: [sanitizers, ubsan, rhel80, clang, static, "8.0", single]
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, "8.0", single]
     commands:
       - command: expansions.update
         params:
@@ -16138,12 +16966,13 @@ tasks:
           mongodb_version: "8.0"
       - func: install_c_driver
         vars:
+          BSON_EXTRA_ALIGNMENT: 1
           SKIP_INSTALL_LIBMONGOCRYPT: 1
       - func: install-uv
       - func: compile
         vars:
+          BSON_EXTRA_ALIGNMENT: 1
           ENABLE_TESTS: "ON"
-          RUN_DISTCHECK: 1
           USE_SANITIZER_UBSAN: "ON"
       - func: fetch-det
       - func: run_kms_servers
@@ -16154,7 +16983,114 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-latest-replica
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, latest, replica]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: replica_set
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: replica
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-latest-sharded
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, latest, sharded]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          TOPOLOGY: sharded_cluster
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: sharded
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
+  - name: sanitizers-ubsan-rhel80-clang-static-extra_alignment-latest-single
+    run_on: rhel80-large
+    tags: [sanitizers, ubsan, rhel80, clang, static, extra_alignment, latest, single]
+    commands:
+      - command: expansions.update
+        params:
+          updates:
+            - { key: build_type, value: Debug }
+            - { key: cc_compiler, value: /opt/mongodbtoolchain/v4/bin/clang }
+            - { key: cxx_compiler, value: /opt/mongodbtoolchain/v4/bin/clang++ }
+            - { key: USE_STATIC_LIBS, value: "1" }
+      - func: setup
+      - func: start_mongod
+        vars:
+          mongodb_version: latest
+      - func: install_c_driver
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          SKIP_INSTALL_LIBMONGOCRYPT: 1
+      - func: install-uv
+      - func: compile
+        vars:
+          BSON_EXTRA_ALIGNMENT: 1
+          ENABLE_TESTS: "ON"
+          USE_SANITIZER_UBSAN: "ON"
+      - func: fetch-det
+      - func: run_kms_servers
+      - func: test
+        vars:
+          MONGOCXX_TEST_TOPOLOGY: single
+          TEST_WITH_UBSAN: "ON"
+          example_projects_cc: clang
+          example_projects_cxx: clang++
+          example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
   - name: sanitizers-ubsan-rhel80-clang-static-latest-replica
     run_on: rhel80-large
     tags: [sanitizers, ubsan, rhel80, clang, static, latest, replica]
@@ -16189,7 +17125,7 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
   - name: sanitizers-ubsan-rhel80-clang-static-latest-sharded
     run_on: rhel80-large
     tags: [sanitizers, ubsan, rhel80, clang, static, latest, sharded]
@@ -16224,7 +17160,7 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
   - name: sanitizers-ubsan-rhel80-clang-static-latest-single
     run_on: rhel80-large
     tags: [sanitizers, ubsan, rhel80, clang, static, latest, single]
@@ -16258,7 +17194,7 @@ tasks:
           example_projects_cc: clang
           example_projects_cxx: clang++
           example_projects_cxxflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fno-omit-frame-pointer
-          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined
+          example_projects_ldflags: -fsanitize=undefined -fno-sanitize-recover=undefined -static-libsan
   - name: scan-build-rhel80-std11-default
     run_on: rhel80-large
     tags: [scan-build, rhel80, std11]
diff --git a/src/bsoncxx/lib/CMakeLists.txt b/src/bsoncxx/lib/CMakeLists.txt
index 02a5c2f8c2..282ed5b9d9 100644
--- a/src/bsoncxx/lib/CMakeLists.txt
+++ b/src/bsoncxx/lib/CMakeLists.txt
@@ -86,6 +86,7 @@ set_dist_list(src_bsoncxx_lib_DIST
     ${bsoncxx_sources_private}
     ${bsoncxx_sources_v_noabi}
     ${bsoncxx_sources_v1}
+    bsoncxx/private/aligned_storage.hh
     bsoncxx/private/b64_ntop.hh
     bsoncxx/private/config/config.hh.in
     bsoncxx/private/convert.hh
diff --git a/src/bsoncxx/lib/bsoncxx/private/aligned_storage.hh b/src/bsoncxx/lib/bsoncxx/private/aligned_storage.hh
new file mode 100644
index 0000000000..fcb84f8a17
--- /dev/null
+++ b/src/bsoncxx/lib/bsoncxx/private/aligned_storage.hh
@@ -0,0 +1,54 @@
+// Copyright 2009-present MongoDB, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <bsoncxx/v1/detail/macros.hpp>
+
+#include <cstddef>
+#include <memory>
+
+namespace bsoncxx {
+
+// Workaround lack of aligned allocation support prior to C++17.
+//
+// Unlike `std::aligned_storage` and `alignas`, this type does NOT propagate alignment requirements to the parent
+// object. This permits correct behavior despite use with regular (alignment-unaware) allocation functions.
+//
+// `alignof(T)` must be explicitly provided by the user for correct behavior, as template parameters do not necessarily
+// inherit attributes such as alignment, e.g. `std::size_t alignment = alignof(T)` does not work as expected.
+template <std::size_t size, std::size_t alignment>
+class aligned_storage {
+    // Sanity check.
+    static_assert(size >= alignment, "sizeof(T) >= alignof(T) must be true");
+
+   private:
+    // We only need at most `alignment` additional bytes to guarantee enough space for alignment.
+    unsigned char _storage[size + alignment];
+
+   public:
+    void* get() BSONCXX_PRIVATE_IF_GNU_LIKE(__attribute__((assume_aligned(alignment))))
+    {
+        void* ptr = _storage;
+        std::size_t space = sizeof(_storage);
+        return std::align(alignment, size, ptr, space);
+    }
+
+    void const* get() const BSONCXX_PRIVATE_IF_GNU_LIKE(__attribute__((assume_aligned(alignment))))
+    {
+        return const_cast<aligned_storage*>(this)->get();
+    }
+};
+
+} // namespace bsoncxx
diff --git a/src/bsoncxx/lib/bsoncxx/private/stack.hh b/src/bsoncxx/lib/bsoncxx/private/stack.hh
index e1f8c2f7b0..caf08c27ba 100644
--- a/src/bsoncxx/lib/bsoncxx/private/stack.hh
+++ b/src/bsoncxx/lib/bsoncxx/private/stack.hh
@@ -18,6 +18,8 @@
 #include <memory>
 #include <type_traits>
 
+#include <bsoncxx/private/bson.hh>
+
 namespace bsoncxx {
 
 // Note: This stack is only intended for use with the 'frame' type in
@@ -78,6 +80,17 @@ class stack {
         new (_get_ptr()) T(std::forward<Args>(args)...);
     }
 
+    template <typename... Args>
+    void emplace_back(bson_t* bson, Args&&... args) {
+        if (_is_empty) {
+            _is_empty = false;
+        } else {
+            _inc();
+        }
+
+        new (_get_ptr()) T(bson, std::forward<Args>(args)...);
+    }
+
     void pop_back() {
         _get_ptr()->close();
         _dec();
@@ -92,7 +105,7 @@ class stack {
     }
 
    private:
-    typename std::aligned_storage<sizeof(T)>::type _object_memory[size];
+    alignas(T) unsigned char _object_memory[size * sizeof(T)];
 
     std::list<T*> _buckets;
 
diff --git a/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp b/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp
index ccafacd58e..1b06149488 100644
--- a/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp
+++ b/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp
@@ -22,6 +22,7 @@
 #include <bsoncxx/types.hpp>
 #include <bsoncxx/types/bson_value/view.hpp>
 
+#include <bsoncxx/private/aligned_storage.hh>
 #include <bsoncxx/private/bson.hh>
 #include <bsoncxx/private/itoa.hh>
 #include <bsoncxx/private/make_unique.hh>
@@ -44,7 +45,7 @@ void bson_free_deleter(std::uint8_t* ptr) {
 class managed_bson_t {
    public:
     managed_bson_t() {
-        bson_init(&bson);
+        bson_init(bson_ptr);
     }
 
     managed_bson_t(managed_bson_t&&) = delete;
@@ -54,15 +55,16 @@ class managed_bson_t {
     managed_bson_t& operator=(managed_bson_t const&) = delete;
 
     ~managed_bson_t() {
-        bson_destroy(&bson);
+        bson_destroy(bson_ptr);
     }
 
     bson_t* get() {
-        return &bson;
+        return bson_ptr;
     }
 
    private:
-    bson_t bson;
+    bsoncxx::aligned_storage<sizeof(bson_t), alignof(bson_t)> bson_storage;
+    bson_t* bson_ptr = new (bson_storage.get()) bson_t;
 };
 
 } // namespace
@@ -115,7 +117,7 @@ class core::impl {
         if (_stack.empty()) {
             return _root.get();
         } else {
-            return &_stack.back().bson;
+            return _stack.back().bson_ptr;
         }
     }
 
@@ -201,14 +203,22 @@ class core::impl {
 
    private:
     struct frame {
+        ~frame() = default;
+
+        frame(frame&&) = delete;
+        frame& operator=(frame&&) = delete;
+
+        frame(frame const&) = delete;
+        frame& operator=(frame const&) = delete;
+
         frame(bson_t* parent, char const* key, std::int32_t len, bool is_array)
             : n(0), is_array(is_array), parent(parent) {
             if (is_array) {
-                if (!bson_append_array_begin(parent, key, len, &bson)) {
+                if (!bson_append_array_begin(parent, key, len, bson_ptr)) {
                     throw bsoncxx::v_noabi::exception{error_code::k_cannot_begin_appending_array};
                 }
             } else {
-                if (!bson_append_document_begin(parent, key, len, &bson)) {
+                if (!bson_append_document_begin(parent, key, len, bson_ptr)) {
                     throw bsoncxx::v_noabi::exception{error_code::k_cannot_begin_appending_document};
                 }
             }
@@ -216,11 +226,11 @@ class core::impl {
 
         void close() {
             if (is_array) {
-                if (!bson_append_array_end(parent, &bson)) {
+                if (!bson_append_array_end(parent, bson_ptr)) {
                     throw bsoncxx::v_noabi::exception{error_code::k_cannot_end_appending_array};
                 }
             } else {
-                if (!bson_append_document_end(parent, &bson)) {
+                if (!bson_append_document_end(parent, bson_ptr)) {
                     throw bsoncxx::v_noabi::exception{error_code::k_cannot_end_appending_document};
                 }
             }
@@ -228,7 +238,8 @@ class core::impl {
 
         std::size_t n;
         bool is_array;
-        bson_t bson;
+        bsoncxx::aligned_storage<sizeof(bson_t), alignof(bson_t)> bson_storage;
+        bson_t* bson_ptr = new (bson_storage.get()) bson_t;
         bson_t* parent;
     };
 
diff --git a/src/mongocxx/lib/mongocxx/private/client_session.hh b/src/mongocxx/lib/mongocxx/private/client_session.hh
index f12442c2a4..8b69ce56a3 100644
--- a/src/mongocxx/lib/mongocxx/private/client_session.hh
+++ b/src/mongocxx/lib/mongocxx/private/client_session.hh
@@ -25,6 +25,7 @@
 
 #include <mongocxx/options/transaction.hh>
 
+#include <bsoncxx/private/aligned_storage.hh>
 #include <bsoncxx/private/bson.hh>
 #include <bsoncxx/private/helpers.hh>
 
@@ -123,7 +124,7 @@ class client_session::impl {
             return bsoncxx::helpers::view_from_bson_t(ct);
         }
 
-        return bsoncxx::helpers::view_from_bson_t(&_empty_cluster_time);
+        return bsoncxx::helpers::view_from_bson_t(_empty_cluster_time_ptr);
     }
 
     bsoncxx::v_noabi::types::b_timestamp operation_time() const noexcept {
@@ -236,7 +237,9 @@ class client_session::impl {
 
     unique_session _session_t;
 
-    bson_t _empty_cluster_time = BSON_INITIALIZER;
+    // Just a long-lasting empty bson_t. Destruction is not required.
+    bsoncxx::aligned_storage<sizeof(bson_t), alignof(bson_t)> _empty_cluster_time_storage;
+    bson_t const* _empty_cluster_time_ptr = new (_empty_cluster_time_storage.get()) bson_t BSON_INITIALIZER;
 };
 
 } // namespace v_noabi
diff --git a/src/mongocxx/lib/mongocxx/private/mock.hh b/src/mongocxx/lib/mongocxx/private/mock.hh
index e584ef0bad..f9494c7086 100644
--- a/src/mongocxx/lib/mongocxx/private/mock.hh
+++ b/src/mongocxx/lib/mongocxx/private/mock.hh
@@ -14,6 +14,8 @@
 
 #pragma once
 
+#include <bsoncxx/v1/detail/macros.hpp>
+
 #include <array>
 #include <cassert>
 #include <functional>
@@ -28,14 +30,64 @@
 
 #include <bsoncxx/stdx/type_traits.hpp>
 
+#include <bsoncxx/private/bson.hh>
+
 namespace mongocxx {
 namespace test_util {
 
+template <typename CRTP, typename R>
+struct mock_invoke_fn {
+    template <typename Self, typename... Args>
+    static R invoke(Self self, Args... args) {
+        auto crtp = static_cast<CRTP*>(self);
+        auto instance = crtp->active_instance();
+        if (instance) {
+            while (!instance->_callbacks.empty()) {
+                if (instance->_callbacks.top()._conditional(args...)) {
+                    return instance->_callbacks.top()._callback(args...);
+                }
+                instance->_callbacks.pop();
+            }
+        }
+
+        return crtp->_func(args...);
+    }
+};
+
+template <typename CRTP, typename T>
+struct mock_invoke;
+
+template <typename CRTP, typename R, typename... Args>
+struct mock_invoke<CRTP, R(Args...)> {
+    R operator()(Args... args) {
+        return mock_invoke_fn<CRTP, R>::invoke(this, args...);
+    }
+};
+
+BSONCXX_PRIVATE_WARNINGS_PUSH();
+BSONCXX_PRIVATE_WARNINGS_DISABLE(GNU("-Wignored-attributes"));
+
+template <typename CRTP, typename... Args>
+struct mock_invoke<CRTP, bson_t const*(Args...)> {
+    bson_t const* operator()(Args... args) {
+        return mock_invoke_fn<CRTP, bson_t const*>::invoke(this, args...);
+    }
+};
+
+template <typename CRTP, typename... Args>
+struct mock_invoke<CRTP, bson_t*(Args...)> {
+    bson_t* operator()(Args... args) {
+        return mock_invoke_fn<CRTP, bson_t*>::invoke(this, args...);
+    }
+};
+
+BSONCXX_PRIVATE_WARNINGS_POP();
+
 template <typename T>
 class mock;
 
 template <typename R, typename... Args>
-class mock<R(MONGOCXX_ABI_CDECL*)(Args...)> {
+class mock<R(MONGOCXX_ABI_CDECL*)(Args...)> : public mock_invoke<mock<R(MONGOCXX_ABI_CDECL*)(Args...)>, R(Args...)> {
    public:
     using underlying_ptr = R (*)(Args...);
     using callback = std::function<R(Args...)>;
@@ -43,6 +95,7 @@ class mock<R(MONGOCXX_ABI_CDECL*)(Args...)> {
 
     class rule {
         friend mock;
+        friend mock_invoke_fn<mock<R(MONGOCXX_ABI_CDECL*)(Args...)>, R>;
 
        public:
         rule(callback callback) : _callback(std::move(callback)) {
@@ -68,6 +121,7 @@ class mock<R(MONGOCXX_ABI_CDECL*)(Args...)> {
 
     class instance {
         friend mock;
+        friend mock_invoke_fn<mock<R(MONGOCXX_ABI_CDECL*)(Args...)>, R>;
 
        public:
         instance(instance const&) = delete;
@@ -126,26 +180,13 @@ class mock<R(MONGOCXX_ABI_CDECL*)(Args...)> {
     };
 
     friend instance;
+    friend mock_invoke_fn<mock<R(MONGOCXX_ABI_CDECL*)(Args...)>, R>;
 
     mock(underlying_ptr func) : _func(std::move(func)) {}
     mock(mock&&) = delete;
     mock(mock const&) = delete;
     mock& operator=(mock const&) = delete;
 
-    R operator()(Args... args) {
-        auto instance = active_instance();
-        if (instance) {
-            while (!instance->_callbacks.empty()) {
-                if (instance->_callbacks.top()._conditional(args...)) {
-                    return instance->_callbacks.top()._callback(args...);
-                }
-                instance->_callbacks.pop();
-            }
-        }
-
-        return _func(args...);
-    }
-
     std::unique_ptr<instance> create_instance() {
         std::unique_ptr<instance> mock_instance(new instance(this));
         active_instance(mock_instance.get());
diff --git a/src/mongocxx/lib/mongocxx/v_noabi/mongocxx/instance.cpp b/src/mongocxx/lib/mongocxx/v_noabi/mongocxx/instance.cpp
index dff56735a1..61ad506ed9 100644
--- a/src/mongocxx/lib/mongocxx/v_noabi/mongocxx/instance.cpp
+++ b/src/mongocxx/lib/mongocxx/v_noabi/mongocxx/instance.cpp
@@ -75,7 +75,7 @@ void user_log_handler(
 
 // A region of memory that acts as a sentintel value indicating that an instance object is being
 // destroyed. We only care about the address of this object, never its contents.
-typename std::aligned_storage<sizeof(instance), alignof(instance)>::type sentinel;
+alignas(instance) unsigned char sentinel[sizeof(instance)];
 
 std::atomic<instance*> current_instance{nullptr};
 static_assert(std::is_standard_layout<decltype(current_instance)>::value, "Must be standard layout");