Add endpoint-level access control to /v2/user/info

Non-admin users can only query their own user_id. Previously relied
solely on the auth middleware route check, which proxy admins bypass.
This adds defense-in-depth directly in the handler.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

litellm/proxy/management_endpoints/internal_user_endpoints.py

@@ -766,6 +766,19 @@ async def user_info_v2(
                 detail="user_id is required",
             )
 
+        # Non-admin users can only query their own info
+        if (
+            user_api_key_dict.user_role != LitellmUserRoles.PROXY_ADMIN
+            and user_api_key_dict.user_role != LitellmUserRoles.PROXY_ADMIN_VIEW_ONLY
+            and user_id != user_api_key_dict.user_id
+        ):
+            raise HTTPException(
+                status_code=status.HTTP_403_FORBIDDEN,
+                detail="Not allowed to access other user's info. Your user_id={}, requested user_id={}".format(
+                    user_api_key_dict.user_id, user_id
+                ),
+            )
+
         user_info = await prisma_client.get_data(user_id=user_id)
 
         if user_info is None:

tests/test_litellm/proxy/management_endpoints/test_internal_user_endpoints.py

@@ -1508,4 +1508,36 @@ async def test_user_info_v1_has_deprecation_header(mocker):
     assert result.user_id == "test-user"
     # Deprecation headers should be set on the response object
     assert mock_response.headers.get("Deprecation") == "true"
-    assert "successor-version" in mock_response.headers.get("Link", "")
+    assert "successor-version" in mock_response.headers.get("Link", "")
+
+
+@pytest.mark.asyncio
+async def test_user_info_v2_non_admin_cannot_query_other_user(mocker):
+    """
+    Test that a non-admin user gets 403 when querying another user's info
+    via /v2/user/info endpoint handler (defense-in-depth).
+    """
+    from fastapi import Request
+
+    from litellm.proxy._types import ProxyException, UserAPIKeyAuth
+    from litellm.proxy.management_endpoints.internal_user_endpoints import (
+        user_info_v2,
+    )
+
+    mock_prisma_client = mocker.MagicMock()
+    mocker.patch("litellm.proxy.proxy_server.prisma_client", mock_prisma_client)
+
+    mock_request = mocker.MagicMock(spec=Request)
+    mock_user_api_key_dict = UserAPIKeyAuth(
+        user_id="user-A", user_role="internal_user"
+    )
+
+    with pytest.raises(ProxyException) as exc_info:
+        await user_info_v2(
+            user_id="user-B",
+            user_api_key_dict=mock_user_api_key_dict,
+            request=mock_request,
+        )
+
+    assert exc_info.value.code == "403"
+    assert "Not allowed" in str(exc_info.value.message)