The tagDiv Opt-In Builder plugin is vulnerable to Blind SQL Injection via the 'subscriptionCouponId' parameter via the 'create_stripe_subscription' REST API endpoint in versions up to, and including, 1.4.4 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 privileges to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database.