Pinpoint Booking System <= 2.9.9.6.9 - Authenticated (Administrator+) SQL Injection via 'field' Parameter

The Pinpoint Booking System – Version 2 plugin for WordPress is vulnerable to blind SQL Injection via the 'field' parameter in all versions up to, and including, 2.9.9.6.9 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for authenticated attackers, with administrator-level access and above, to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. The nonce required to reach the vulnerable endpoint is emitted on all plugin admin pages loaded under manage_options, making it trivially obtainable by any authenticated administrator.