TrueBooker <= 1.2.3 - Missing Authorization to Unauthenticated Arbitrary User Email Modification via 'admin_addcustomer' AJAX Action

The TrueBooker – Appointment Booking and Scheduler System plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 1.2.3. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for unauthenticated attackers to modify the email address of arbitrary user accounts, including administrators, which can be leveraged to reset the account's password and gain access to it.