Require admin access for budget_limits changes on /key/update

Clearing budget_limits via [] or null is a budget mutation, but
_validate_update_key_data only counted max_budget and spend as budget
changes before deciding whether to skip _check_key_admin_access. A
non-admin key owner or a team member with /key/update could therefore
remove a key's per-window spend caps without admin authorization.

Treat any explicit budget_limits value in the request (set, change, or
clear) as a budget change so it gates through the same admin check as
max_budget. model_fields_set is used because an explicit null is
indistinguishable from an omitted field by value alone.

litellm/proxy/management_endpoints/key_management_endpoints.py

@@ -2254,14 +2254,18 @@ async def _validate_update_key_data(
     # - Anyone else (non-PROXY_ADMIN, not the owner, not a team member
     #   on a team key): must pass _check_key_admin_access (PROXY_ADMIN
     #   / key-owner / team-admin / org-admin of the key).
-    # - max_budget / spend: always require the admin check, even for the
-    #   key owner or a team member (matches the existing admin-only
-    #   budget semantics).
+    # - max_budget / spend / budget_limits: always require the admin
+    #   check, even for the key owner or a team member (matches the
+    #   existing admin-only budget semantics).  budget_limits uses
+    #   model_fields_set because an explicit null/[] clears the field
+    #   and must gate the same as setting or changing it.
     _is_budget_change = (
-        data.max_budget is not None and data.max_budget != existing_key_row.max_budget
-    ) or (
-        data.spend is not None
-        and data.spend != getattr(existing_key_row, "spend", None)
+        (data.max_budget is not None and data.max_budget != existing_key_row.max_budget)
+        or (
+            data.spend is not None
+            and data.spend != getattr(existing_key_row, "spend", None)
+        )
+        or "budget_limits" in data.model_fields_set
     )
 
     # Personal-key bypass: the caller both created the key AND still owns it

tests/test_litellm/proxy/management_endpoints/test_key_management_endpoints.py

@@ -9671,6 +9671,58 @@ class TestKeyOwnerPrivilegeEscalation:
                 )
         mock_check.assert_called_once()
 
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize("cleared_value", [[], None])
+    async def test_creator_cannot_clear_own_budget_limits(self, cleared_value):
+        """Clearing budget_limits is a budget change and requires admin."""
+        data = UpdateKeyRequest(key="sk-test", budget_limits=cleared_value)
+        existing = self._make_existing_key(created_by="creator-123")
+        auth = self._make_auth(user_id="creator-123")
+
+        mock_check = AsyncMock(
+            side_effect=HTTPException(status_code=403, detail="Not authorized")
+        )
+        with patch(
+            "litellm.proxy.management_endpoints.key_management_endpoints._check_key_admin_access",
+            mock_check,
+        ):
+            with pytest.raises(HTTPException):
+                await _validate_update_key_data(
+                    data=data,
+                    existing_key_row=existing,
+                    user_api_key_dict=auth,
+                    llm_router=None,
+                    premium_user=False,
+                    prisma_client=AsyncMock(),
+                    user_api_key_cache=MagicMock(),
+                )
+        mock_check.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_admin_can_clear_budget_limits(self):
+        data = UpdateKeyRequest(key="sk-test", budget_limits=[])
+        existing = self._make_existing_key(created_by="someone-else")
+        auth = UserAPIKeyAuth(
+            user_id="admin-user",
+            user_role=LitellmUserRoles.PROXY_ADMIN,
+        )
+
+        mock_check = AsyncMock()
+        with patch(
+            "litellm.proxy.management_endpoints.key_management_endpoints._check_key_admin_access",
+            mock_check,
+        ):
+            await _validate_update_key_data(
+                data=data,
+                existing_key_row=existing,
+                user_api_key_dict=auth,
+                llm_router=None,
+                premium_user=False,
+                prisma_client=AsyncMock(),
+                user_api_key_cache=MagicMock(),
+            )
+        mock_check.assert_not_called()
+
     @pytest.mark.asyncio
     async def test_admin_can_update_any_field(self):
         data = UpdateKeyRequest(key="sk-test", models=["gpt-4"], max_budget=999.0)