LatePoint <= 5.6.1 - Missing Authorization to Unauthenticated Arbitrary Customer Data Modification via process_step_customer() Booking Form Customer Step

The LatePoint – Calendar Booking Plugin for Appointments and Events plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 5.6.1. 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 personally identifiable information (first name, last name, phone number, and notes) of any existing customer record, including those linked to administrator accounts, by submitting the booking form with a known customer's email address. Exploitation requires the plugin to be configured with guest bookings enabled (is_customer_auth_disabled() returning true), which is necessary for the vulnerable unauthenticated code path in process_step_customer() to be reached.