CVE-2026-35031
CriticalCVSS 9.9Exploitation Probability (EPSS)
Elevated risk51th percentile - higher than 51% of all known CVEs
Summary
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.
Risk Assessment
An attacker with an administrator account or subtitle upload permissions can gain full control over the server, including code execution as root, leading to complete system compromise.
Recommendation
Immediately upgrade Jellyfin to version 10.11.7 or later. If upgrade is not possible, restrict subtitle upload permissions to trusted users only.
Other vulnerabilities in Jellyfin
See all- CVE-2026-35033Critical
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.
- CVE-2026-49246Low
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.
- CVE-2026-49220Medium
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.
- CVE-2026-35034Medium
Jellyfin before version 10.11.7 contains a denial of service vulnerability in the SyncPlay group creation endpoint. An authenticated user can create groups with unlimited name sizes, leading to endpoint lockout and increased memory usage, potentially causing an out-of-memory crash.
- CVE-2026-35032High
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.
- CVE-2023-27161High
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.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS