CVE-2026-47201: CWE-20: Improper Input Validation in goauthentik authentik
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.
AI Analysis
Technical Summary
CVE-2026-47201 describes an XML Signature Wrapping vulnerability in authentik's SAML Source ACS endpoint. The flaw arises from improper input validation (CWE-20) when validating upstream SAML responses. An attacker with a valid account at the upstream identity provider can exploit this by reusing a signed assertion to impersonate another federated user. The vulnerability affects authentik versions prior to 2025.12.5, 2026.2.3, and 2026.5.1. The issue has been addressed in these versions.
Potential Impact
Successful exploitation allows an attacker with low privileges at the upstream IdP to authenticate as any other federated user, resulting in complete compromise of confidentiality, integrity, and availability of the affected authentik service. This can lead to unauthorized access to protected resources and user impersonation.
Mitigation Recommendations
A fix is available in authentik versions 2025.12.5, 2026.2.3, and 2026.5.1. Users should upgrade to one of these versions or later to remediate this vulnerability. Patch status is confirmed by the vendor advisory indicating these versions contain the fix.
CVE-2026-47201: CWE-20: Improper Input Validation in goauthentik authentik
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.
CVSS v3.1
Score 8.5high
Affected software
pkg:golang/github.com/goauthentik/authentikRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-47201 describes an XML Signature Wrapping vulnerability in authentik's SAML Source ACS endpoint. The flaw arises from improper input validation (CWE-20) when validating upstream SAML responses. An attacker with a valid account at the upstream identity provider can exploit this by reusing a signed assertion to impersonate another federated user. The vulnerability affects authentik versions prior to 2025.12.5, 2026.2.3, and 2026.5.1. The issue has been addressed in these versions.
Potential Impact
Successful exploitation allows an attacker with low privileges at the upstream IdP to authenticate as any other federated user, resulting in complete compromise of confidentiality, integrity, and availability of the affected authentik service. This can lead to unauthorized access to protected resources and user impersonation.
Mitigation Recommendations
A fix is available in authentik versions 2025.12.5, 2026.2.3, and 2026.5.1. Users should upgrade to one of these versions or later to remediate this vulnerability. Patch status is confirmed by the vendor advisory indicating these versions contain the fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-18T22:07:37.436Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1f41c3e29bf47b5000d1a4
Added to database: 06/02/2026, 20:49:07 UTC
Last enriched: 06/10/2026, 11:09:59 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 66
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