CVE-2026-35034

Jellyfin prior to version 10.11.7 has an unauthenticated arbitrary file read vulnerability via ffmpeg argument injection through the StreamOptions parameter. An attacker can read server files such as /etc/shadow and exfiltrate their contents as text in the video stream response.

Jellyfin versions prior to 10.11.7 contain a vulnerability chain in the subtitle upload endpoint (POST /Videos/{itemId}/Subtitles), where the Format field is not validated, allowing path traversal via file extension and arbitrary file write. This can be chained into arbitrary file read via .strm files, database extraction, admin privilege escalation, and ultimately remote code execution as root via ld.so.preload.

Jellyfin prior to version 10.11.10 has a vulnerability that allows a specially crafted MKV file with forged filename tags to exploit missing path sanitization during playback. As a result, a malicious MKV file can redirect attachment extraction to any absolute path on disk.

Jellyfin, an open-source media server, prior to version 10.11.9, had a potential XSS vulnerability that allowed a non-privileged user to execute arbitrary Javascript in the context of a logged-in Administrative user. The attack could occur through the Client header during AuthenticateByName.

In Jellyfin prior to version 10.11.7, the LiveTV M3U tuner endpoint (POST /LiveTv/TunerHosts) does not validate the tuner URL, enabling local file read and SSRF attacks. An authenticated user can exploit this to escalate privileges to admin.

An SSRF vulnerability in Jellyfin up to version 10.7.7 allows an attacker to send a crafted POST request to the /Repositories component, enabling access to network resources and sensitive information.