The WP Booking Calendar plugin for WordPress is vulnerable to Unauthenticated Post-Confirmation Booking Manipulation in all versions up to, and including, 10.10. This is due to the plugin not properly requiring re-verification after a booking has been made and a change is being attempted. This makes it possible for unauthenticated attackers to manipulate their confirmed bookings, even after they have been approved.
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.