SAML Vulnerability in Admidio User Management Software
CVE-2026-41670

8.2HIGH

Key Information:

Vendor

Admidio

Status
Admidio
Vendor
CVE Published:
7 May 2026

What is CVE-2026-41670?

Admidio, an open-source user management solution, contains a vulnerability in its SSO module's SAML IdP implementation. Prior to version 5.0.9, the system fails to validate the AssertionConsumerServiceURL value from incoming SAML AuthnRequest messages against the registered ACS URL in its database. This oversight allows an attacker, who is aware of the Entity ID of a registered service provider client, to fabricate a SAML AuthnRequest with a malicious AssertionConsumerServiceURL. Consequently, the IdP may send a signed SAML response containing sensitive user identity attributes (such as login name, email, roles, and profile fields) to a URL controlled by the attacker. This critical issue has been addressed in version 5.0.9, highlighting the importance of upgrading to secure user data.

Affected Version(s)

admidio < 5.0.9

References

https://github.com/Admidio/admidio/security/advisories/GH...
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https://github.com/Admidio/admidio/releases/tag/v5.0.9
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CVSS V3.1

Score:
8.2
Severity:
HIGH
Confidentiality:
High
Integrity:
Low
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.