The Booking for Appointments and Events Calendar – Amelia Pro plugin for WordPress is vulnerable to time-based SQL Injection via the 'tag[] (array KEYS)' parameter in all versions up to, and including, 9.9.1 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. WordPress's wp_magic_quotes escapes array values but not array keys, meaning attacker-controlled tag[] array keys reach EventRepository::getFilteredIds() completely unescaped and can be crafted to defeat the plugin's Statement::execute placeholder binder via overlapping strtr() substitution keys.