CVE-2026-49246 — Jellyfin: Potential MKV attachment filename path traversal to RCE

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
jellyfin / jellyfin	affected < 10.11.10

CWE

CWE-22

References

https://github.com/jellyfin/jellyfin/security/advisories/GHSA-f47c-m7gr-q92j

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.