CVE-2026-47201 PUBLISHED

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

Assigner: GitHub_M
Reserved: 18.05.2026 Published: 02.06.2026 Updated: 03.06.2026

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.

Metrics

CVSS 3.1

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

Attack Vector	Network	Scope	Changed
Attack Complexity	High	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	goauthentik
Product	authentik
Versions	Version < 2025.12.5 is affected Version < 2026.2.3 is affected Version < 2026.5.1 is affected

References

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

Problem Types

CWE-20: Improper Input Validation CWE