Admidio: Event participation IDOR - non-leaders can register other users for events via user_uuid parameter

Vulnerability In modules/events/eventsfunction.php, the event participation logic allows any user who can participate in an event to register OTHER users by manipulating the useruuid GET parameter. Line 47: $getUserUuid = admFuncVariableIsValid$GET, 'useruuid', 'uuid', ... Line 424: if...