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.