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TI-2026-36443 Aliases CVE-2026-49246

Jellyfin: Potential MKV attachment filename path traversal to RCE

Priority LOW 10CWE-22Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0037 31st percentileScored 2026-11-07
Fix Fixed jellyfin (jellyfin): 10.11.10

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
jellyfinjellyfinbefore 10.11.1010.11.10Patch availableCNA
  • jellyfin Vendorjellyfin Affected before 10.11.10 Fixed in 10.11.10 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:jellyfin:jellyfin:*:*:*:*:*:*:*:*——jellyfin
  • cpe:2.3:a:jellyfin:jellyfin:*:*:*:*:*:*:*:* Versions — — ·jellyfin

Remediation

  • Fix · CNA jellyfin (jellyfin) Fixed in 10.11.10

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-49246

References

Other 1

  • TI-2021-04500 Unauthenticated Arbitrary File Access in Jellyfin CVSS 3.1HIGH 7.7
  • TI-2023-26761 Argument Injection in FFmpeg codec parameters in Jellyfin CVSS 3.1HIGH 8.8
  • TI-2021-10203 Unauthenticated GET requests through Remote Image endpoints CVSS 3.1MEDIUM 5.8
  • TI-2023-09464 In Jellyfin 10.8.x through 10.8.3, the name of a playlist is vulnerable to stored XSS. CVSS 3.1MEDIUM 5.4
  • TI-2023-09463 In Jellyfin 10.8.x through 10.8.3, the name of a collection is vulnerable to stored XSS. CVSS 3.1MEDIUM 5.4
  • TI-2026-24405 Jellyfin Possible Organization/Secret Compromise from dangerous CI implementation CVSS 3.1CRITICAL 10.0
See all 25 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences