Slink before 1.12.3 Missing Authorization on Image Comment Endpoints

Slink before 1.12.3 fails to properly authorize access to image comment endpoints, allowing unauthenticated attackers to read comment threads via GET /api/image/{imageId}/comments and server-sent-events subscriptions. Attackers who obtain image IDs out of band can retrieve full comment threads on public images and subscribe to live comment updates without authentication or authorization checks.