The Ultimate Gift Cards for WooCommerce plugin for WordPress is vulnerable to boolean-based SQL Injection via the 'default_price' and 'product_id' parameters in all versions up to, and including, 3.1.4 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.