chore(proxy): cherry-pick #28547 onto patch/v1.85.1

[yuneng-berri]

Backport of #28547 (d480ffda3c) onto patch/v1.85.1.

Routes the remaining path-dependent call sites in auth, ACL, routing, and audit-log decisions through get_request_route(request) so they read from the ASGI scope["path"] instead of request.url.path. The helper itself already exists on v1.85.1 (added by #27878); this PR extends the helper's usage to the additional sites listed below.

Sites routed through get_request_route

• _experimental/mcp_server/auth/user_api_key_auth_mcp.py
• management_endpoints/mcp_management_endpoints.py
• vector_store_endpoints/utils.py
• pass_through_endpoints/pass_through_endpoints.py
• auth/route_checks.py
• litellm_pre_call_utils.py
• spend_tracking/spend_management_endpoints.py
• common_utils/http_parsing_utils.py
• management_helpers/utils.py
• health_endpoints/_health_endpoints.py

Conflict resolution

Cherry-pick applied cleanly with no conflicts. All 11 files plus the test file are pure request.url.path → get_request_route(request) swaps with the lazy auth_utils import (no feature drift).

Test plan

• uv run pytest tests/proxy_unit_tests/test_proxy_routes.py -v
• make test-unit

[greptile-apps]

Greptile Summary

This cherry-pick from #28547 closes a Host-header path-smuggling gap on the patch/v1.85.1 branch: Starlette's request.url.path re-parses the URL using the Host header, so a crafted value like localhost/?x=1 collapses the path to "/", which could flip auth, ACL, and routing decisions. The fix routes all remaining call sites through the already-existing get_request_route(request) helper, which reads the authoritative route from scope["path"] (uvicorn's parse of the HTTP request line).

• 10 call sites migrated across auth, MCP, vector-store ACL, pass-through, spend-log, and OTel audit-log paths — all mechanical request.url.path → get_request_route(request) swaps with inline imports to avoid the proxy import cycle.
• Tests extended with 7 new parametric cases in test_proxy_routes.py that construct requests with malformed Host headers and assert each call site resolves the route from the ASGI scope rather than the (manipulable) URL.

Confidence Score: 5/5

Safe to merge — all changes are targeted substitutions of a single helper call with no logic additions or removals, and the test file gains coverage without weakening any existing assertions.

Every changed line is a direct swap of request.url.path for get_request_route(request), a helper already tested and used on this branch since #27878. The cherry-pick applied cleanly, inline imports are correctly scoped and consistently documented, and the dropped or '' guard in the MCP management endpoint is safe because get_request_route always returns a str. The new tests exercise the exact bypass vectors described in the PR and do not relax any pre-existing assertions.

No files require special attention.

Important Files Changed

Filename	Overview
litellm/proxy/auth/auth_utils.py	Updated docstring for get_request_route to explain the ASGI scope-vs-url.path security rationale; no logic changes.
litellm/proxy/_experimental/mcp_server/auth/user_api_key_auth_mcp.py	Replaces three request.url.path usages with get_request_route for /.well-known/ bypass guard and OAuth2 path checks; inline import added for cycle safety.
litellm/proxy/auth/route_checks.py	_is_assistants_api_request now reads route from scope["path"] via get_request_route instead of request.url.path.
litellm/proxy/management_endpoints/mcp_management_endpoints.py	PKCE token-endpoint detection now uses get_request_route; the original (request.url.path or "") None-guard is dropped since get_request_route always returns str.
litellm/proxy/management_helpers/utils.py	Two OTel audit-log call sites that assigned _route from request.url.path now use get_request_route.
litellm/proxy/litellm_pre_call_utils.py	_get_metadata_variable_name path check (thread/assistant detection) migrated to get_request_route.
litellm/proxy/common_utils/http_parsing_utils.py	_add_vector_store_id_from_path now extracts vector_store_id from scope path rather than url.path.
litellm/proxy/vector_store_endpoints/utils.py	Four endpoint-match calls use scope path for ACL decisions in both vector-store and vector-store-files permission checks.
litellm/proxy/spend_tracking/spend_management_endpoints.py	ui_view_spend_logs v2-path detection migrated to get_request_route.
litellm/proxy/pass_through_endpoints/pass_through_endpoints.py	create_pass_through_route inner handler path variable now reads from scope.
litellm/proxy/health_endpoints/_health_endpoints.py	test_endpoint diagnostic route-echo updated to use get_request_route.
tests/proxy_unit_tests/test_proxy_routes.py	Adds 7 new parametric test cases covering each migrated call site; only reformats the existing malformed-Host test, no assertion weakening.

_{Reviews (1): Last reviewed commit: "chore(proxy): cherry-pick #28547 onto pa..." | Re-trigger Greptile}

[codecov]

Codecov Report

❌ Patch coverage is 9.52381% with 19 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
litellm/proxy/management_helpers/utils.py	0.00%	4 Missing ⚠️
litellm/proxy/vector_store_endpoints/utils.py	0.00%	4 Missing ⚠️
...erimental/mcp_server/auth/user_api_key_auth_mcp.py	0.00%	3 Missing ⚠️
...itellm/proxy/health_endpoints/_health_endpoints.py	0.00%	2 Missing ⚠️
...y/management_endpoints/mcp_management_endpoints.py	0.00%	2 Missing ⚠️
...y/pass_through_endpoints/pass_through_endpoints.py	0.00%	2 Missing ⚠️
...proxy/spend_tracking/spend_management_endpoints.py	0.00%	2 Missing ⚠️

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