CVE-2026-49247: Jellyfin: Potential Authenticated path traversal in /ClientLog/Document
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Jellyfinto a version that resolves this vulnerability.Fixed in 10.11.10
Event History
Frequently Asked Questions
What is the severity of CVE-2026-49247?
CVE-2026-49247 has a severity rating of 8.8, indicating it is high risk.
How do I fix CVE-2026-49247?
To fix CVE-2026-49247, upgrade Jellyfin to version 10.11.11 or later to mitigate the vulnerability.
What type of vulnerability is CVE-2026-49247?
CVE-2026-49247 is classified as a path traversal vulnerability.
What versions of Jellyfin are affected by CVE-2026-49247?
Jellyfin versions from 10.9.0 to 10.11.10 are affected by CVE-2026-49247.
What impact could CVE-2026-49247 have on my system?
CVE-2026-49247 could allow an authenticated attacker to perform path traversal attacks, potentially exposing sensitive files.