Quick answers
- Is CVE-2026-35033 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-35033 being exploited in the wild.
- How severe is CVE-2026-35033?
- Critical severity, with a CVSS score of 9.1, published 14 April 2026.
- Which products and versions are affected?
- Jellyfin < 10.11.7.
- Is there a fix for CVE-2026-35033?
- A patch was published on 2023-03-31: Version 10.11.7 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-35033 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-35033?
- 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
An argument injection vulnerability exists in Jellyfin's `ParseStreamOptions` method within `StreamingHelpers.cs`. The application fails to validate lowercase query parameters, allowing an attacker to bypass regex filters and inject arbitrary arguments into the ffmpeg command line. Specifically, by manipulating the `h264-level` parameter, an attacker can inject a `drawtext` filter with a `textfile` argument to read files like `/etc/shadow`. While the `/Videos/{itemId}/stream` endpoint lacks an authorization attribute, an attacker must still know or obtain a pseudorandom item GUID to successfully trigger the exploit. The issue is resolved in version 10.11.7 by improving input sanitization.
Affected products
- Jellyfin Jellyfin < 10.11.7
Timeline
- 2023-03-31: patched: Version 10.11.7 released
- 2026-04-14: advisory: Security advisory and CVE published