CVSS8.8
Severityhigh
WeaknessCWE-22
ExploitedNot in CISA KEV
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.