CVE-2026-49220 Jellyfin: Potential XSS in user management
A non-privileged user can inject JavaScript via the Client header, leading to arbitrary code execution in an administrator's browser session.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-49220?
CVE-2026-49220 is a medium-severity cross-site scripting vulnerability in jellyfin, published on 24 Jun 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Jellyfin is an open source self hosted media server. Prior to 10.11.9, a potential XSS attack exists in Jellyfin which can allow a non-privileged user to execute arbitrary Javascript in the context of a logged-in Administrative user, resulting in numerous potential issues. The Client header during an AuthenticateByName can contain arbitrary HTML and Javascript, which will then be executed by the Administrative user when visiting the Access tab of the user in question from within the dashboard. This vulnerability is fixed in 10.11.9.
Weakness: CWE-79
Which versions are affected by CVE-2026-49220?
How do I fix CVE-2026-49220?
No fix has been published for CVE-2026-49220 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-49220 being exploited?
There is no known exploitation of CVE-2026-49220 in the wild and no public exploit code.
Sources
Also known as GHSA-fv79-gmhx-xh2v.