Vulnerability Description
Jellyfin is an open source self hosted media server. Prior to 10.11.10, a specifically crafted MKV file containing forged filename tags can be leveraged to exploit missing path sanitization during playback. Jellyfin treats the MKV file name tag on MKV attachments as trusted and passes it unsanitized into Path.Combine(attachmentFolder, fileName) inside PathManager.GetAttachmentPath. Because .NET's Path.Combine neither normalises .. nor rejects a rooted second argument, a crafted MKV can redirect Jellyfin's MKV attachment extraction to any absolute path on disk. This triggers on any playback action of the affected video on a client which will attempt to burn in the subtitles by default.g This vulnerability is fixed in 10.11.10.
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-49246?
CVE-2026-49246 is a documented vulnerability. Jellyfin is an open source self hosted media server. Prior to 10.11.10, a specifically crafted MKV file containing forged filename tags can be leveraged to exploit missing path sanitization during pla...
How severe is CVE-2026-49246?
CVSS scoring is not yet available for CVE-2026-49246. Check NVD for updates.
Is there a patch for CVE-2026-49246?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.