admidio up to 5.0.8 SSO Module smc_acs_url AssertionConsumerServiceURL assertion

Summaryinfo

A vulnerability identified as critical has been detected in admidio up to 5.0.8. Affected by this issue is the function smc_acs_url of the component SSO Module. The manipulation of the argument AssertionConsumerServiceURL leads to assertion. This vulnerability is traded as CVE-2026-41670. It is possible to initiate the attack remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in admidio up to 5.0.8 and classified as critical. This issue affects the function smc_acs_url of the component SSO Module. The manipulation of the argument AssertionConsumerServiceURL with an unknown input leads to a assertion vulnerability. Using CWE to declare the problem leads to CWE-617. The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Admidio is an open-source user management solution. Prior to version 5.0.9, the SAML IdP implementation in Admidio's SSO module uses the AssertionConsumerServiceURL value directly from incoming SAML AuthnRequest messages as the destination for the SAML response, without validating it against the registered ACS URL (smc_acs_url) stored in the database for the corresponding service provider client. An attacker who knows the Entity ID of a registered SP client can craft a SAML AuthnRequest with an arbitrary AssertionConsumerServiceURL, causing the IdP to send the signed SAML response -- containing user identity attributes (login name, email, roles, profile fields) -- to an attacker-controlled URL. This issue has been patched in version 5.0.9.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-41670 since 04/22/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 5.0.9 eliminates this vulnerability. The upgrade is hosted for download at github.com.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• admidio

Version

• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4
• 5.0.5
• 5.0.6
• 5.0.7
• 5.0.8

Website

• Product: https://github.com/Admidio/admidio/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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