Funnel Builder for WooCommerce Checkout < 3.15.0.3 Missing Authorization via AJAX

Funnel Builder for WooCommerce Checkout prior to 3.15.0.3 contains a missing authorization vulnerability in the public checkout endpoint that allows unauthenticated attackers to invoke internal methods and write arbitrary data to the plugin's External Scripts global setting. Attackers can inject malicious JavaScript through the External Scripts setting that executes in the browsers of all checkout page visitors.