Path traversal in Jellyfin - CVE-2026-35031
Published: April 15, 2026 / Updated: April 17, 2026
Vulnerability identifier: #VU126129
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Green
CVE-ID: CVE-2026-35031
CWE-ID: CWE-22
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: Jellyfin
Affected software:
Jellyfin
Jellyfin
Detailed vulnerability description
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to path traversal in the subtitle upload endpoint when processing the Format field in subtitle upload requests. A remote user can upload a specially crafted subtitle to write arbitrary files and chain the issue to execute arbitrary code.
Exploitation requires the Upload Subtitles permission.
How to mitigate CVE-2026-35031
Install security update from vendor's website.