CVE-2026-42849: Goauthentik Authentik

Critical severity, CVSS 9.3. EPSS: 0.5% chance of exploitation in the next 30 days.

authentik is an open-source identity provider. Prior to versions 2025.12.5 and 2026.2.3, due to the implementation of stages in the SFE (Simple Flow Executor) in order to make the interface more compatible with legacy browsers, it was possible to use an XSS exploit in the AutosubmitStage. This issue has been patched in versions 2025.12.5 and 2026.2.3.

Affected products

• Goauthentik Authentik: before 2025.12.5 (fixed in 2025.12.5); from 2026.2.0, before 2026.2.3 (fixed in 2026.2.3)

Published 2026-06-02. Last modified 2026-07-22.