Access violation vulnerability in SoundCloud Is Gold 2.5.1

The Soundcloud Is Gold plugin for WordPress is vulnerable to changes made without permission. In versions up to, and including, 2.5.1, the soundcloud_is_gold_add_user() function, which is called via an AJAX action, does not have the necessary security checks in place. This means that people who have at least a subscriber-level of access can add additional Soundcloud usernames without permission.