CVE-2026-49246
Prior to 10.11.10, a specifically crafted MKV file containing forged filename tags can be leveraged to exploit missing path sanitization during playback.
Does this matter?
Lower severity and a low EPSS score (0.37%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 1.7 LOWCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.37% probability · 31th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Source
- security-advisories@github.com
EPSS 0.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.