The Hydra Booking – Appointment Scheduling & Booking Calendar plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 1.2.1 via the /wp-json/hydra-booking/v1/booking/details/{id} REST endpoint. This is due to the getBookingDetails() callback only enforcing the tfhb_manage_options capability via tfhb_manage_options_permission(), without verifying that the requested booking belongs to the currently authenticated host (the lookup in getBookingDetailsData() filters solely on the booking id supplied in the URL). This makes it possible for authenticated attackers, with Hydra Host-level access and above (a role created by the plugin which grants tfhb_manage_options), to view sensitive booking records belonging to other hosts, including attendee names, emails, phone numbers, addresses, meeting details, payment method and status, transaction history, and internal notes by iterating booking IDs.