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 Signature Wrapping when validating upstream SAML responses. An attacker with any account at the upstream IdP can reuse a valid signed assertion to authenticate as another federated user. This issue has been patched in versions 2025.12.5, 2026.2.3, and 2026.5.1.

authentik is an open-source identity provider. Prior to versions 2025.12.6, 2026.2.4, and 2026.5.1, the Source stage can be bypassed by sending an empty POST. This issue has been patched in versions 2025.12.6, 2026.2.4, and 2026.5.1.

authentik is an open-source identity provider. Prior to versions 2025.12.5 and 2026.2.3, the SAML source response processor (ResponseProcessor.parse()) does not validate the Conditions element on assertions. NotBefore, NotOnOrAfter, and AudienceRestriction are all ignored. This allows replay of expired assertions and acceptance of assertions intended for other service providers. This issue has been patched in versions 2025.12.5 and 2026.2.3.

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.

authentik is an open-source identity provider. Prior to version 2026.2.3, the WS-Federation provider validates the user-supplied wreply parameter using a raw string prefix check rather than proper URL parsing. An attacker who can craft a login link can supply a wreply value on a different origin that passes the check (e.g. https://portal.example.com.evil.tld/), causing the victim's browser to POST the signed WS-Federation login response to attacker-controlled infrastructure. This issue has been patched in version 2026.2.3.

authentik is an open-source identity provider. Prior to versions 2025.12.6, 2026.2.4, and 2026.5.1, an attacker with the ability to change a source connection, and an account in one of the configured sources can log into any account. This issue has been patched in versions 2025.12.6, 2026.2.4, and 2026.5.1.

authentik is an open-source identity provider. Versions 2025.12.4 and prior, and versions 2026.2.0-rc1 through 2026.2.2 were vulnerable to Authentication Bypass through SAML NameID XML Comment Injection. Due to how authentik extracted the NameID value from a SAML assertion, it was possible for an attacker to trick authentik into only seeing a part of the NameID value, potentially allowing an attacker to gain access to other accounts. This issue could be exploited on an authentik instance with a SAML Source, where the attacker had an account on the SAML Source and the ability to modify their NameID value (commonly username or E-mail), and XML Signing was enabled. The attacker could modify the SAML assertion given to authentik by injecting a comment within the NameID value, which effectively truncated the NameID value to the snippet before the comment, and gave the attacker access to any user account. This issue has been fixed in versions 2025.12.5 and 2026.2.3.

authentik is an open-source identity provider. Prior to 2025.8.6, 2025.10.4, and 2025.12.4, when using a SAML Source that has the option Verify Assertion Signature under Verification Certificate enabled and not Verify Response Signature, or does not have the Encryption Certificate setting under Advanced Protocol settings configured, it was possible for an attacker to inject a malicious assertion before the signed assertion that authentik would use instead. authentik 2025.8.6, 2025.10.4, and 2025.12.4 fix this issue.

authentik is an open-source identity provider. Prior to 2025.10.4 and 2025.12.4, with a malformed cookie it was possible to bypass authentication when using forward authentication in the authentik Proxy Provider when used in conjunction with Traefik or Caddy as reverse proxy. When a malicious cookie was used, none of the authentik-specific X-Authentik-* headers were set which depending on application can grant access to an attacker. authentik 2025.10.4 and 2025.12.4 fix this issue.

authentik is an open-source identity provider. From 2021.3.1 to before 2025.8.6, 2025.10.4, and 2025.12.4, when using delegated permissions, a User that has the permission Can view * Property Mapping or Can view Expression Policy is able to execute arbitrary code within the authentik server container through the test endpoint, which is intended to preview how a property mapping/policy works. authentik 2025.8.6, 2025.10.4, and 2025.12.4 fix this issue.