The Events Manager – Calendar, Bookings, Tickets, and more! plugin for WordPress is vulnerable to generic SQL Injection via Stored 'meta_key

The Events Manager – Calendar, Bookings, Tickets, and more! plugin for WordPress is vulnerable to generic SQL Injection via Stored 'meta_key' via Event/Location Duplicate Action in all versions up to, and including, 7.4.0 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 contributor-level access and above, to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. This is a second-order SQL injection: an attacker first plants SQL metacharacters in a custom meta key via the standard add-meta flow (WordPress stores these verbatim in wp_postmeta), then triggers the injection by invoking the event_duplicate or location_duplicate action, which reads the stored meta keys via get_post_meta() and concatenates them unsafely into the INSERT query.