admidio up to 5.0.8 Endpoint introspect improper authentication

Summaryinfo

A vulnerability, which was classified as critical, has been found in admidio up to 5.0.8. This issue affects some unknown processing of the file /modules/sso/index.php/oidc/introspect of the component Endpoint. Performing a manipulation results in improper authentication. This vulnerability is identified as CVE-2026-41671. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in admidio up to 5.0.8. It has been classified as critical. This affects an unknown functionality of the file /modules/sso/index.php/oidc/introspect of the component Endpoint. The manipulation with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Admidio is an open-source user management solution. Prior to version 5.0.9, the OIDC token introspection endpoint (/modules/sso/index.php/oidc/introspect) always returns {"active": true} for every request, regardless of whether a valid token is provided, whether the token is expired, revoked, or completely fabricated. The endpoint performs no authentication of the calling resource server and no validation of the submitted token. Any resource server that relies on this introspection endpoint to validate access tokens will accept all requests as authorized, enabling complete authentication bypass. Additionally, the OIDC token revocation endpoint (/oidc/revoke) returns {"revoked": true} without actually revoking any token, preventing resource servers from invalidating compromised credentials. This issue has been patched in version 5.0.9.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-41671 since 04/22/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. 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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