Auth bypass in Jellyfin
CVE-2026-35033
Jellyfin is an open source self hosted media server. Versions prior to 10.11.7 contain an unauthenticated arbitrary file read vulnerability via ffmpeg argument injection through the StreamOptions query parameter parsing mechanism. The ParseStreamOptions method in StreamingHelpers.cs adds any lowercase query parameter to a dictionary without validation, bypassing the RegularExpression attribute on the level controller parameter, and the unsanitized value is concatenated directly into the ffmpeg command line. By injecting a drawtext filter with a textfile argument, an attacker can read arbitrary server files such as /etc/shadow and exfiltrate their contents as text rendered in the video stream response. The vulnerable /Videos/{itemId}/stream endpoint has no Authorize attribute, making this exploitable without authentication, though item GUIDs are pseudorandom and require an authenticated user to obtain. This issue has been fixed in version 10.11.7.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (42.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Jellyfin — versions < 10.11.7
Weakness classification (CWE)
References
- github.com/jellyfin/jellyfin/security/advisories/GHSA-jh22-fw8w-2v9x (Vendor Advisory)
- github.com/jellyfin/jellyfin/releases/tag/v10.11.7 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-35033?
- CVE-2026-35033 is a critical-severity vulnerability in Jellyfin, classified under Argument Injection. CVSS score: 9.1/10. Published 2026-04-14.
- How severe is CVE-2026-35033?
- Critical severity. CVSS v3 base score is 9.1 out of 10.