The Community Events plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the ajax_admin_event_approval() function in all versions up to, and including, 1.5.6. This makes it possible for unauthenticated attackers to approve arbitrary events via the 'eventlist' parameter.
https://plugins.trac.wordpress.org/browser/community-events/trunk/community-events.php#L160
https://plugins.trac.wordpress.org/browser/community-events/tags/1.5.5/community-events.php#L64
https://plugins.trac.wordpress.org/browser/community-events/tags/1.5.5/community-events.php#L160