ApostropheCMS is an open-source Node.js content management system. Prior to 4.33.0, the notification module exposes PATCH and DELETE REST endpoints that perform operations directly on the underlying MongoDB collection without verifying that the requester is authenticated or owns the target notification. As a result, an unauthenticated attacker who obtains a valid notification ID can modify or permanently delete another user's notification. This issue is fixed in version 4.33.0.