Booking for Appointments and Events Calendar – Amelia <= 2.1.2 - Unauthenticated Authorization Bypass via Remote Approval Endpoint

The Booking for Appointments and Events Calendar – Amelia plugin for WordPress is vulnerable to Improper Authorization in all versions up to, and including, 2.1.2. This is due to a logical short-circuit flaw in authorization logic that causes token validation to be entirely skipped when a booking has a 'waiting' status. This makes it possible for unauthenticated attackers to approve any booking that is in 'waiting' status by sending a crafted request to the publicly-accessible admin-ajax endpoint.