diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index bb48b5a41466..94eb3273c049 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -5734,7 +5734,7 @@ private CodegenSecurity defaultCodegenSecurity(String key, SecurityScheme securi
         cs.name = key;
         cs.description = securityScheme.getDescription();
         cs.type = securityScheme.getType().toString();
-        cs.isCode = cs.isPassword = cs.isApplication = cs.isImplicit = cs.isOpenId = false;
+        cs.isCode = cs.isPassword = cs.isApplication = cs.isImplicit = cs.isOpenId = cs.isOAuth = false;
         cs.isHttpSignature = false;
         cs.isBasicBasic = cs.isBasicBearer = false;
         cs.scheme = securityScheme.getScheme();
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
index 056a55a95d88..f1aca92f0c05 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
@@ -5036,6 +5036,19 @@ public void testQueryIsJsonMimeType() {
         assertTrue(codegenOperation.queryParams.stream().allMatch(p -> p.queryIsJsonMimeType));
     }
 
+    @Test
+    public void testDefaultOauthIsNotNull() {
+        final DefaultCodegen codegen = new DefaultCodegen();
+        final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_1/issue_20662.yaml");
+        codegen.setOpenAPI(openAPI);
+        List<CodegenSecurity> securitySchemes = codegen.fromSecurity(openAPI.getComponents().getSecuritySchemes());
+        assertThat(securitySchemes.size()).isEqualTo(1);
+        CodegenSecurity openIdScheme = securitySchemes.get(0);
+        assertNotNull(openIdScheme.isOAuth);
+        assertFalse(openIdScheme.isOAuth);
+        assertTrue(openIdScheme.isOpenId);
+    }
+
     private List<String> getRequiredVars(CodegenModel model) {
         return getNames(model.getRequiredVars());
     }
diff --git a/modules/openapi-generator/src/test/resources/3_1/issue_20662.yaml b/modules/openapi-generator/src/test/resources/3_1/issue_20662.yaml
new file mode 100644
index 000000000000..feef456b68a8
--- /dev/null
+++ b/modules/openapi-generator/src/test/resources/3_1/issue_20662.yaml
@@ -0,0 +1,22 @@
+openapi: 3.1.0
+info:
+  title: Security scheme test
+  version: 1.0.0
+paths:
+  /test:
+    get:
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                type: string
+components:
+  securitySchemes:
+    openId:
+      type: openIdConnect
+      openIdConnectUrl: https://localhost:8443
+security:
+  - openId:
+      - test
\ No newline at end of file