THe WCFM Membership plugin for WordPress is vulnerable to privilege escalation in versions up to, and including 2.10.0, due to a missing capability check on the wp_ajax_nopriv_wcfm_ajax_controller AJAX action that controls membership settings. This makes it possible for unauthenticated attackers to modify the membership registration form in a way that allows them to set the role for registration to that of any user including administrators. Once configured, the attacker can then register as an administrator.