Description
Sonarr is a PVR for Usenet and BitTorrent users. Versions prior to 4.0.16.2942 have an authentication bypass that affected users that had disabled authentication for local addresses (Authentication Required set to: `Disabled for Local Addresses`) without a reverse proxy running in front of Sonarr that didn't not pass through the invalid header. Patches are available in version 4.0.16.2942 in the nightly/develop branch and version 4.0.16.2944 for stable/main releases. Some workarounds are available. Make sure Sonarr's Authentication Required setting is set to `Enabled`, run Sonarr behind a reverse proxy, and/or do not expose Sonarr directly to the internet and instead rely on accessing it through a VPN, Tailscale or a similar solution.
Problem types
CWE-290: Authentication Bypass by Spoofing
Product status
References
github.com/...Sonarr/security/advisories/GHSA-h5qx-5hjf-7c9r
github.com/Sonarr/Sonarr/releases/tag/v4.0.16.2942
github.com/Sonarr/Sonarr/releases/tag/v4.0.16.2944