CVE-2023-49096: Jellyfin is a Free Software Media System for managing and streaming media.

Jellyfin is a Free Software Media System for managing and streaming media.

Jellyfin is a Free Software Media System for managing and streaming media. In affected versions there is an argument injection in the VideosController, specifically the `/Videos/<itemId>/stream` and `/Videos/<itemId>/stream.<container>` endpoints which are present in the current Jellyfin version. Additional endpoints in the AudioController might also be vulnerable, as they differ only slightly in execution. Those endpoints are reachable by an unauthenticated user. In order to exploit this vulnerability an unauthenticated attacker has to guess an itemId, which is a completely random GUID. It’s a very unlikely case even for a large media database with lots of items. Without an additional information leak, this vulnerability shouldn’t be directly exploitable, even if the instance is reachable from the Internet. There are a lot of query parameters that get accepted by the method. At least two of those, videoCodec and audioCodec are vulnerable to the argument injection. The values can be traced through a lot of code and might be changed in the process. However, the fallback is to always use them as-is, which means we can inject our own arguments. Those arguments land in the command line

Description from the National Vulnerability Database, published by GitHub

What it means for a small business

If your business uses jellyfin, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 1.3%, higher than 69% of CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

Weekly security brief

The flaws that hit local websites, every Friday.

One short email: what got exploited this week, which WordPress plugins broke, and what to check. Unsubscribe in one click.