Quick answers
- Is CVE-2026-49247 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-49247 being exploited in the wild.
- How severe is CVE-2026-49247?
- High severity, with a CVSS score of 8.8, published 24 June 2026.
- Which products and versions are affected?
- Jellyfin >= 10.9.0, < 10.11.10.
- Is there a fix for CVE-2026-49247?
- A patch was published on 2026-06-24: Fix released in version 10.11.10 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-49247 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-49247?
- Check whether you run Jellyfin at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A path traversal vulnerability (CWE-22) exists in the POST /ClientLog/Document endpoint of Jellyfin media servers. The application fails to sanitize the 'Client' and 'Version' fields within the Authorization header, using them directly to construct file paths for log storage. An authenticated, non-privileged attacker can use directory traversal sequences (e.g., '../') to write arbitrary content to any location accessible by the Jellyfin service account, though the resulting file will have a forced '.log' extension. This issue is a regression of a previous fix (CVE-2023-30626) that was not correctly merged into the master branch. The vulnerability is resolved in version 10.11.10.
Affected products
- Jellyfin Jellyfin >= 10.9.0, < 10.11.10
Timeline
- 2026-06-10: advisory: GitHub Security Advisory published
- 2026-06-24: disclosed: NVD publication date
- 2026-06-24: patched: Fix released in version 10.11.10