Easy!Appointments is a self hosted appointment scheduler. In versions up to and including 1.5.2, the booking reschedule view at "/index.php/booking/reschedule/{appointment_hash}" (handled by "Booking::index()") embeds the entire customer record as inline JavaScript ("const vars = {... "customer_data": {...}, ...}") without authentication and without field whitelisting. Anyone in possession of the 12-character "appointment_hash" — which appears in plain text in reschedule emails, confirmation page URLs, and operator-side calendar links — can read every column of that customer's row in the "ea_users" table. Version 1.6.0 contains a patch.