The Slider Hero plugin for WordPress is vulnerable to second-order SQL Injection in versions up to, and including, 9.1.7 via the qcld_sliderhero_duplicate() function. Slide data (description, title, btn, btn2, image_link, custom, etc.) is stored safely via $wpdb->update() with %s placeholders in the qchero_save_image AJAX handler, but when an administrator triggers the 'heroduplicateslider' task, qcld_sliderhero_duplicate() re-reads every slide column and concatenates the raw values directly into an INSERT VALUES tuple that is then executed with $wpdb->query() — with no $wpdb->prepare(), esc_sql(), or _real_escape_string in between. 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.