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5.3

Admidio User Management Software Allows Unwanted User Registration

GHSA-7pfv-hr63-h7cw CVE-2026-30927 GHSA-7pfv-hr63-h7cw
Summary

An outdated version of Admidio's user management software allows anyone who can join an event to sign up or remove others from events, even if they're not authorized to do so. This is a security concern because it lets unauthorized users make changes to event participation. To fix this, update Admidio to version 5.0.6 or later.

What to do
  • Update admidio admidio to version 5.0.6.
  • Update admidio admidio/admidio to version 5.0.6.
Affected software
VendorProductAffected versionsFix available
admidio admidio <= 5.0.6 5.0.6
admidio admidio/admidio <= 5.0.6 5.0.6
Original title
Admidio is an open-source user management solution. Prior to 5.0.6, in modules/events/events_function.php, the event participation logic allows any user who can participate in an event to register ...
Original description
Admidio is an open-source user management solution. Prior to 5.0.6, in modules/events/events_function.php, the event participation logic allows any user who can participate in an event to register OTHER users by manipulating the user_uuid GET parameter. The condition uses || (OR), meaning if possibleToParticipate() returns true (event is open for participation), ANY user - not just leaders - can specify a different user_uuid and register/cancel participation for that user. The code then operates on $user->getValue('usr_id') (the target user from user_uuid) rather than the current user. This vulnerability is fixed in 5.0.6.
ghsa CVSS4.0 5.3
Vulnerability type
CWE-639 Authorization Bypass Through User-Controlled Key
Published: 10 Mar 2026 · Updated: 13 Mar 2026 · First seen: 9 Mar 2026