diff --git a/litellm/proxy/health_endpoints/_health_endpoints.py b/litellm/proxy/health_endpoints/_health_endpoints.py
index 6b35f41deb5..6282d3894f7 100644
--- a/litellm/proxy/health_endpoints/_health_endpoints.py
+++ b/litellm/proxy/health_endpoints/_health_endpoints.py
@@ -1881,6 +1881,11 @@ async def test_model_connection(  # noqa: PLR0915
                         config_litellm_params = dict(
                             deployments[0].get("litellm_params", {})
                         )
+                        # Authorize against the matched deployment's owner, not
+                        # the caller-supplied model_info (same as the id path).
+                        resolved_model_info = dict(
+                            deployments[0].get("model_info", {}) or {}
+                        )
             except Exception as e:
                 verbose_proxy_logger.debug(
                     f"Could not find model {model_name} in router: {e}. "
diff --git a/litellm/proxy/management_endpoints/model_management_endpoints.py b/litellm/proxy/management_endpoints/model_management_endpoints.py
index ccb49bf7fcd..713d386de5b 100644
--- a/litellm/proxy/management_endpoints/model_management_endpoints.py
+++ b/litellm/proxy/management_endpoints/model_management_endpoints.py
@@ -135,19 +135,19 @@ def _strip_credentials_on_destination_change(
     patch_plaintext: dict,
     db_plaintext: "Callable[[str], object]",
 ) -> None:
-    """If the patch changes a destination field (api_base/base_url/custom_llm_provider)
-    without supplying a fresh credential, drop the inherited secret(s) from the
-    merged params so a stored credential is never silently re-pointed at a new
-    (possibly attacker-controlled) endpoint."""
+    """When a destination field (api_base/base_url/provider endpoint) changes,
+    drop every INHERITED credential — one the patch did not itself supply — so a
+    stored secret is never silently re-pointed at a new (possibly attacker-
+    controlled) endpoint. Cleared per field: supplying one credential must not
+    preserve the others."""
     destination_changed = any(
         field in patch_plaintext and patch_plaintext[field] != db_plaintext(field)
         for field in _DESTINATION_LITELLM_PARAMS
     )
-    supplied_new_credential = any(
-        field in patch_plaintext for field in _CREDENTIAL_LITELLM_PARAMS
-    )
-    if destination_changed and not supplied_new_credential:
-        for field in _CREDENTIAL_LITELLM_PARAMS:
+    if not destination_changed:
+        return
+    for field in _CREDENTIAL_LITELLM_PARAMS:
+        if field not in patch_plaintext:
             merged_litellm_params.pop(field, None)
 
 
diff --git a/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py b/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py
index 69189522f68..2c9aae51b69 100644
--- a/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py
+++ b/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py
@@ -1987,3 +1987,45 @@ def test_reject_inherited_credential_redirect_helper():
         config_litellm_params={"api_key": "sk-x"},
         request_litellm_params={"model": "gpt-4o"},
     )
+
+
+@pytest.mark.asyncio
+async def test_test_connection_model_name_path_authorizes_against_resolved_owner():
+    """When the deployment is resolved by model_name (no id), auth must still run
+    against the resolved deployment's owner, not the caller-supplied model_info."""
+    victim_deployment = {
+        "model_name": "victim-model",
+        "litellm_params": {
+            "model": "azure/gpt-4o",
+            "api_key": "sk-victim",
+            "api_base": "https://victim.example/v1",
+        },
+        "model_info": {"id": "victim-id", "team_id": "team-OWNER"},
+    }
+    mock_router = MagicMock()
+    mock_router.get_deployment.return_value = None  # no id resolution
+    mock_router.get_model_list.return_value = [victim_deployment]
+
+    captured = {}
+
+    async def _capture(*, model_params, **kwargs):
+        captured["team_id"] = model_params.model_info.team_id
+        return True
+
+    mock_auth = AsyncMock(side_effect=_capture)
+    mock_ahealth = AsyncMock(return_value={"status": "healthy"})
+
+    with contextlib.ExitStack() as stack:
+        for p in _health_test_connection_patches(
+            MagicMock(), mock_router, mock_auth, mock_ahealth
+        ):
+            stack.enter_context(p)
+        await health_test_model_connection(
+            request=MagicMock(),
+            mode="chat",
+            litellm_params={"model": "victim-model"},  # resolved by name, no id
+            model_info={"team_id": "team-ATTACKER"},
+            user_api_key_dict=MagicMock(user_id="attacker", token="t"),
+        )
+
+    assert captured.get("team_id") == "team-OWNER"
diff --git a/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py b/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py
index f3d3a8a8b9b..867002d6192 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py
@@ -2480,3 +2480,26 @@ class TestModelMgmtAuthzHardening:
             model_info=None,
             user_api_key_dict=self._admin(),
         )
+
+    def test_destination_change_clears_inherited_credential_per_field(self):
+        from litellm.proxy.management_endpoints.model_management_endpoints import (
+            _strip_credentials_on_destination_change,
+        )
+
+        # Patch redirects api_base AND supplies an UNRELATED credential
+        # (aws_secret_access_key); the inherited api_key must still be dropped.
+        merged = {
+            "api_key": "sk-inherited",
+            "aws_secret_access_key": "supplied",
+            "api_base": "https://attacker.example",
+        }
+        patch_plaintext = {
+            "api_base": "https://attacker.example",
+            "aws_secret_access_key": "supplied",
+        }
+        db = {"api_base": "https://real.example", "api_key": "sk-inherited"}
+        _strip_credentials_on_destination_change(
+            merged, patch_plaintext, lambda f: db.get(f)
+        )
+        assert "api_key" not in merged  # inherited, not re-supplied -> dropped
+        assert merged.get("aws_secret_access_key") == "supplied"  # supplied -> kept