Easy Appointments <= 3.12.21 - Unauthenticated Sensitive Information Exposure via REST API

The Easy Appointments plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 3.12.21 via the `/wp-json/wp/v2/eablocks/ea_appointments/` REST API endpoint. This is due to the endpoint being registered with `'permission_callback' => '__return_true'`, which allows access without any authentication or authorization checks. This makes it possible for unauthenticated attackers to extract sensitive customer appointment data including full names, email addresses, phone numbers, IP addresses, appointment descriptions, and pricing information.