CVE-2026-49247 Jellyfin: Potential Authenticated path traversal in /ClientLog/Document
Authenticated users can exploit path traversal in the ClientLog endpoint to write arbitrary files to the server filesystem.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-49247?
CVE-2026-49247 is a high-severity path traversal vulnerability in jellyfin, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Jellyfin is an open source self hosted media server. From 10.9.0 until 10.11.10, the POST /ClientLog/Document endpoint accepts the Authorization header's Client and Version fields and uses them unsanitized as components of the on-disk filename when persisting client-uploaded log documents. As a result, any authenticated non-admin user can include ../ sequences in the Client field to cause Jellyfin to write attacker-controlled content to arbitrary paths reachable by the Jellyfin service user, with a forced .log suffix. This vulnerability is fixed in 10.11.10.
Weakness: CWE-22
Which versions are affected by CVE-2026-49247?
How do I fix CVE-2026-49247?
No fix has been published for CVE-2026-49247 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-2026-49247 being exploited?
There is no known exploitation of CVE-2026-49247 in the wild and no public exploit code.
Sources
Also known as GHSA-jg92-mrxq-vv75.