authentik: Authentication bypass via assertion confusion in SAML sources
Published Sep 24, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
authentik: Authentication bypass via assertion confusion in SAML sources
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
authentik is an open-source identity provider. Prior to 2026.2.7, 2026.5.7, and 2026.8.2, an authentik SAML Source verifies an assertion's signature and validity period but does not ensure that the identity provider issued the assertion for that Source or in response to a login request from that Source. The SAML Source also does not record already accepted assertions, allowing replay. An unauthenticated actor who possesses such a valid assertion can use an assertion intended for another service provider or reuse an earlier assertion to authenticate as the user named by the assertion. Only SAML Sources are affected; SAML Providers and other Source types are not affected. This issue is fixed in versions 2026.2.7, 2026.5.7, and 2026.8.2.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- Security advisory ↗
- Source repository ↗
- Source repository ↗
- Source repository ↗
- Source repository ↗
- Patch commit ↗
- Patch commit ↗
- Patch commit ↗
- Patch commit ↗
- https://docs.goauthentik.io/releases/2026.2#fixed-in-202627 ↗
- https://docs.goauthentik.io/releases/2026.5#fixed-in-202657 ↗
- https://docs.goauthentik.io/releases/2026.8#fixed-in-202682 ↗
Record history
Published Sep 24, 2026 · Last refreshed Nov 3, 2026