CVE-2024-43801

Technical Description

Jellyfin is an open source self hosted media server. The Jellyfin user profile image upload accepts SVG files, allowing for a stored XSS attack against an admin user via a specially crafted malicious SVG file. When viewed by an admin outside of the Jellyfin Web UI (e.g. via "view image" in a browser), this malicious SVG file could interact with the browser's LocalStorage and retrieve an AccessToken, which in turn can be used in an API call to elevate the target user to a Jellyfin administrator. The actual attack vector is unlikely to be exploited, as it requires specific actions by the administrator to view the SVG image outside of Jellyfin's WebUI, i.e. it is not a passive attack. The underlying exploit mechanism is solved by PR #12490, which forces attached images (including the potential malicious SVG) to be treated as attachments and thus downloaded by browsers, rather than viewed. This prevents exploitation of the LocalStorage of the browser. This PR has been merged and the releva

Remediation

Check the references section for vendor advisories and patches from jellyfin. Update jellyfin to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References