Admin Notices Manager <= 1.4.0 - Missing Authorization to Authenticated (Subscriber+) User Email Retrieval

The Admin Notices Manager plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the handle_ajax_call() function in all versions up to, and including, 1.4.0. This makes it possible for authenticated attackers, with subscriber-level access and above, to retrieve a list of registered user emails.