Appointment Booking Plugin <= 5.7.3 - Insecure Direct Object Reference to Unauthenticated Sensitive Information Disclosure via 'booking[id]' and 'cart[id]' Parameters

The Appointment Booking Plugin – LatePoint | Calendar & Scheduling for WordPress plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 5.7.3 via the booking[id] and cart[id] parameters on the steps__reload_booking_form_summary_panel and steps__start public routes (reachable through wp_ajax_nopriv_latepoint_route_call). This is due to OsStepsHelper::set_required_objects() feeding raw request parameters into set_booking_object() and set_cart_object(), which call OsModel::set_data() and load an arbitrary booking or cart row by primary key with no ownership check — the ownership guard the vendor added for the earlier disclosure lives only inside OsStepsHelper::load_step() and does not cover the sibling routes or cart[id] at all. This makes it possible for unauthenticated attackers to enumerate sequential booking / cart identifiers and read other customers' appointment details (service name, agent, date/time, duration, price breakdown, status) and other shoppers' pending checkout contents directly from the JSON responses.