CVE-2026-73291 Seerr: Path traversal to RCE via /avatarproxy image cache filename from upstream ETag
Attackers can exploit path traversal in the image proxy to overwrite files and execute code on the server.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-73291?
CVE-2026-73291 is a high-severity path traversal vulnerability in seerr-team seerr, published on 12 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Prior to version 3.4.0, Seerr's ImageProxy in server/lib/imageproxy.ts uses the upstream ETag and Content-Type response headers to build a cache filename for the unauthenticated GET /avatarproxy/:jellyfinUserId route, allowing a malicious or compromised Jellyfin or Emby server, or a man-in-the-middle attacker on a plaintext media-server connection, to supply traversal sequences that path.join and fs.writeFile normalize outside the cache directory, overwrite /app/dist/index.js or other files, and execute code as the node user after a container restart. This issue is fixed in version 3.4.0.
Which versions are affected by CVE-2026-73291?
How do I fix CVE-2026-73291?
No fix has been published for CVE-2026-73291 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-73291 being exploited?
There is no known exploitation of CVE-2026-73291 in the wild and no public exploit code.
Sources
Also known as GHSA-mc6w-69r3-62h8.