WP Review Slider Pro <= 12.6.8 - Authenticated (Subscriber+) SQL Injection via 'stypes' Parameter

The WP Review Slider Pro plugin for WordPress is vulnerable to SQL Injection via the 'stypes' and 'slocations' parameters of the wppro_get_overall_chart_data AJAX action in versions up to, and including, 12.6.8. This is due to the use of stripslashes() on user-supplied JSON strings prior to json_decode(), which removes the escaping applied by WordPress's wp_magic_quotes; the resulting decoded array values are then concatenated directly into SQL WHERE clauses without parameterization, and the constructed query is executed via $wpdb->get_results() without $wpdb->prepare(). This makes it possible for authenticated attackers, with Subscriber-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 handler also returns the executed SQL string in its JSON response, which simplifies oracle construction for blind exploitation.