CVE-2026-73291

Seerr (open-source media manager for Jellyfin/Plex/Emby) prior to v3.4.0 contains a flaw in ImageProxy: the code uses upstream ETag and Content-Type headers to build the cache filename for the unauthenticated GET /avatarproxy/:jellyfinUserId route. This allows a malicious or compromised Jellyfin/...