CVE-2026-35031:
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.
Score
A numerical rating that indicates how dangerous this vulnerability is.
9.9Critical- Published Date:Apr 14, 2026
- CISA KEV Date:*No Data*
- Industries Affected:20
Threat Predictions
- EPSS Score:0.2
- EPSS Percentile:48%
Exploitability
- Score:3.1
- Attack Vector:NETWORK
- Attack Complexity:LOW
- Privileges Required:LOW
- User Interaction:NONE
- Scope:CHANGED
Impact
- Score:6.0
- Confidentiality Impact:HIGH
- Integrity Impact:HIGH
- Availability Impact:HIGH
Description Preview
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.
Industries Affected
Below is a list of industries most commonly impacted or potentially at risk based on intelligence.
