The flaw is a context key injection in the PropertyMapping test endpoint of authentik. A user with delegated permissions to view property mapping or expression policy can supply arbitrary Python code through the context key, which the server evaluates during the preview. This results in remote code execution inside the authentik container, providing the attacker full control over the service process.

The affected vendor is goauthentik:authentik. Versions from 2021.3.1 up through those just before 2025.8.6, 2025.10.4, and 2025.12.4 contain the vulnerability. The releases 2025.8.6, 2025.10.4, and 2025.12.4 include the fix and are not affected.

The CVSS score of 9.1 marks this as a very high impact flaw, but the EPSS score of less than 1% indicates a low current exploitation probability. It is not listed in the CISA KEV catalog. An attacker requires authenticated access with the specific view permissions, so the attack vector is likely internal or authenticated remote; the flaw does not allow unauthenticated network exploitation. Once the test endpoint is invoked by a privileged user, the injected code runs with the privileges of the authentik process.