The Advanced Shipment Tracking for WooCommerce plugin for WordPress is vulnerable to SQL Injection via the tracking_provider parameter of the POST /wp-json/wc-ast/v3/orders/<order_id>/shipment-trackings REST endpoint in all versions up to, and including, 3.9. This is due to insufficient escaping on the user-supplied parameter and lack of sufficient preparation on the existing SQL query in WC_Advanced_Shipment_Tracking_Admin::get_provider_slug_from_name() — the value is concatenated directly into the format string of $wpdb->prepare() rather than bound as a parameter, bypassing parameterised-query protections. This makes it possible for authenticated attackers, with Shop Manager-level access and above, to append additional SQL queries into the already-existing query that can be used to extract sensitive information from the database.