chore(proxy): treat stored credential-name as an inherited credential in the health connection-test guard

The connection-test endpoint already refuses to forward an inherited inline key to a caller-overridden destination; extend that to a deployment whose credential is stored by reference (litellm_credential_name) so the same destination-override exfiltration path is closed for it too. Matches the credential set used on the model-management write paths.

litellm/proxy/health_endpoints/_health_endpoints.py

@@ -80,6 +80,7 @@ def _reject_os_environ_references(params: dict) -> None:
 
 _HEALTH_CREDENTIAL_FIELDS = (
     "api_key",
+    "litellm_credential_name",
     "aws_secret_access_key",
     "aws_session_token",
     "vertex_credentials",

tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py

@@ -1968,6 +1968,15 @@ def test_reject_inherited_credential_redirect_helper():
             config_litellm_params={"api_key": "sk-x", "api_base": "https://real"},
             request_litellm_params={"api_base": "https://attacker"},
         )
+    # inherited stored-credential-NAME (no inline api_key) + override -> also rejected
+    with pytest.raises(HTTPException):
+        _reject_inherited_credential_redirect(
+            config_litellm_params={
+                "litellm_credential_name": "openai-cred",
+                "api_base": "https://real",
+            },
+            request_litellm_params={"api_base": "https://attacker"},
+        )
     # request supplies its own credential -> allowed
     _reject_inherited_credential_redirect(
         config_litellm_params={"api_key": "sk-x"},