The MotoPress Hotel Booking plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 6.0.1. 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 overwrite or delete the internal notes (_mphb_booking_internal_notes) of any booking by supplying an arbitrary booking ID. The nonce for this action is output in the HTML source of every public page through wp_localize_script (MPHB._data.nonces), so any unauthenticated visitor can obtain a valid nonce and perform the action without any account or prior interaction.