WP Activity Log <= 4.5.0 - Missing Capabilities Check to User Enumeration

The WP Activity Log plugin for WordPress is vulnerable to authorization bypass due to a missing capability check on the handle_ajax_call function in versions up to, and including, 4.5.0. This makes it possible for authenticated attackers, with subscriber-level access or higher, to obtain a list of users with accounts on the site. This includes ids, usernames and emails.