fix(proxy): require admin for any /key/update spend, reject non-finite

Gate the admin check on the presence of `spend` (not a value diff): the
DB spend lags the live cross-pod counter, so an "unchanged" spend on the
non-admin path let a key owner / team member overwrite the live counter
below real usage. Also reject NaN/+-inf spend before the DB write.

litellm/proxy/management_endpoints/key_management_endpoints.py

@@ -69,6 +69,7 @@ from litellm.proxy.management_endpoints.common_utils import (
     _is_user_team_admin,
     _set_object_metadata_field,
     _team_member_has_permission,
+    validate_finite_spend,
 )
 from litellm.proxy.management_endpoints.model_management_endpoints import (
     _add_model_to_db,
@@ -2204,6 +2205,9 @@ async def _validate_update_key_data(
     user_api_key_cache: Any,
 ) -> None:
     """Validate permissions and constraints for key update."""
+    # Reject NaN/±inf spend before it can reach the DB / spend counter.
+    validate_finite_spend(data.spend)
+
     _is_proxy_admin = user_api_key_dict.user_role == LitellmUserRoles.PROXY_ADMIN.value
 
     _check_allowed_routes_caller_permission(
@@ -2263,12 +2267,14 @@ async def _validate_update_key_data(
     #   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.
+    # - spend gates on presence alone (not a value diff): the DB spend
+    #   lags the live cross-pod counter, so letting an "unchanged" spend
+    #   through the non-admin path would let a key owner / team member
+    #   overwrite the live counter below real usage and silently weaken
+    #   enforcement.
     _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)
-        )
+        or data.spend is not None
         or "budget_limits" in data.model_fields_set
     )
 

tests/test_litellm/proxy/management_endpoints/test_key_management_endpoints.py

@@ -9718,6 +9718,39 @@ class TestKeyOwnerPrivilegeEscalation:
         assert exc_info.value.status_code == 403
         mock_check.assert_called_once()
 
+    @pytest.mark.asyncio
+    async def test_creator_cannot_reset_own_spend_to_stale_value(self):
+        """Submitting `spend` equal to the stale DB value must still require
+        admin. The DB spend lags the live cross-pod counter, so an
+        "unchanged" spend on the non-admin path would let the creator
+        overwrite the live counter below real usage. Any explicit `spend`
+        is a budget change, regardless of value match."""
+        existing = self._make_existing_key(created_by="creator-123")
+        existing.spend = 0.0
+        # spend equals the stale DB value (0.0) — the old `!=` gate skipped
+        # the admin check here.
+        data = UpdateKeyRequest(key="sk-test", spend=0.0)
+        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_assigned_user_blocked_from_model_escalation(self):
         data = UpdateKeyRequest(key="sk-test", models=["gpt-4", "claude-opus"])