Vulnerability · Published Apr 14, 2026 · Assigned by GitHub_M
CVE-2026-35031Jellyfin: Potential RCE via subtitle upload path traversal + .strm chain
Critical 10.0
In plain English
A critical-severity improper input validation in jellyfin from jellyfin. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 55% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
Jellyfin is an open source self hosted media server. 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 the file extension and enabling arbitrary file write. This arbitrary file write 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. Exploitation requires an administrator account or a user that has been explicitly granted the "Upload Subtitles" permission. This issue has been fixed in version 10.11.7. If users are unable to upgrade immediately, they can grant non-administrator users Subtitle upload permissions to reduce attack surface.
Affected products (as reported)
Weakness: CWE-20, CWE-22, CWE-187 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
References
- https://github.com/jellyfin/jellyfin/security/advisories/GHSA-j2hf-x4q5-47j3 x_refsource_CONFIRM
- https://github.com/jellyfin/jellyfin/releases/tag/v10.11.7 x_refsource_MISC