Easy!Appointments has unauthenticated customer PII disclosure on booking reschedule page

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.