CVE-2026-47201

authentik: XML Signature Wrapping in SAML Source ACS allows authentication as arbitrary federated user

State: Published
Severity: 8.5 High
Published: Jun 2, 2026
Updated: Jun 3, 2026
Reserved: May 18, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	8.5 High	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H	GitHub_M

Weaknesses

CWE-20 Improper Input Validation

Affected Products

Product	Versions
authentikgoauthentik	< 2025.12.5Affected < 2026.2.3Affected < 2026.5.1Affected

References

https://github.com/goauthentik/authentik/security/advisories/GHSA-c3m2-jqmq-pvp3

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