authentik is an open-source identity provider. Prior to versions 2025.12.5, 2026.2.3, and 2026.5.1, authentik's SAML Source ACS endpoint is vulnerable to XML Si…

Published:

1 juni 2026 om 22:00:00

Alert date:

2 juni 2026 om 22:02:38

Source:

nvd.nist.gov

Identity & Access, Web Technologies

A critical vulnerability in authentik's open-source identity provider allows XML Signature Wrapping attacks on SAML Source ACS endpoints. Attackers with upstream IdP accounts can reuse valid signed assertions to authenticate as different federated users. The vulnerability affects versions prior to 2025.12.5, 2026.2.3, and 2026.5.1. Patches are available in the specified fixed versions. This represents a significant authentication bypass risk in federated identity environments.

Technical details

Mitigation steps:

Affected products:

authentik