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 is an improper input validation vulnerability (CWE-20) in the goauthentik authentik product's SAML Source ACS endpoint. Before versions 2025.12.5, 2026.2.3, and 2026.5.1, the endpoint improperly validates upstream SAML responses, enabling XML Signature Wrapping attacks. This allows an attacker with any account at the upstream identity provider to reuse a valid signed assertion to authenticate as another federated user. The issue is fixed in the stated versions.
Potential Impact
Successful exploitation allows an attacker with a valid upstream IdP account to impersonate any federated user by reusing a signed SAML assertion. This compromises confidentiality, integrity, and availability of the authentication process, potentially granting unauthorized access to protected resources.
Mitigation Recommendations
Upgrade authentik to version 2025.12.5, 2026.2.3, 2026.5.1, or later to apply the official fix addressing this vulnerability. Patch status is confirmed by the vendor's versioning information. No alternative mitigations are indicated.
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
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-47201 is an improper input validation vulnerability (CWE-20) in the goauthentik authentik product's SAML Source ACS endpoint. Before versions 2025.12.5, 2026.2.3, and 2026.5.1, the endpoint improperly validates upstream SAML responses, enabling XML Signature Wrapping attacks. This allows an attacker with any account at the upstream identity provider to reuse a valid signed assertion to authenticate as another federated user. The issue is fixed in the stated versions.
Potential Impact
Successful exploitation allows an attacker with a valid upstream IdP account to impersonate any federated user by reusing a signed SAML assertion. This compromises confidentiality, integrity, and availability of the authentication process, potentially granting unauthorized access to protected resources.
Mitigation Recommendations
Upgrade authentik to version 2025.12.5, 2026.2.3, 2026.5.1, or later to apply the official fix addressing this vulnerability. Patch status is confirmed by the vendor's versioning information. No alternative mitigations are indicated.
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: 6/2/2026, 8:49:07 PM
Last enriched: 6/2/2026, 9:03:46 PM
Last updated: 6/2/2026, 10:02:28 PM
Views: 5
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.