Jellyfin: Potential Authenticated path traversal in /ClientLog/Document
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Jellyfin is an open source self hosted media server. From 10.9.0 until 10.11.10, the POST /ClientLog/Document endpoint accepts the Authorization header's Client and Version fields and uses them unsanitized as components of the on-disk filename when persisting client-uploaded log documents. As a result, any authenticated non-admin user can include ../ sequences in the Client field to cause Jellyfin to write attacker-controlled content to arbitrary paths reachable by the Jellyfin service user, with a forced .log suffix. This vulnerability is fixed in 10.11.10.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA jellyfin (jellyfin) Fixed in 10.11.10
Timeline
- 2026-10-02 Threatist record created from CVE-2026-49247
More jellyfin vulnerabilities
- 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
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences