The Payment Button for PayPal plugin for WordPress is vulnerable to unauthorized order creation in all versions up to, and including, 1.2.3.41. This is due to the plugin exposing a public AJAX endpoint (`wppaypalcheckout_ajax_process_order`) that processes checkout results without any authentication or server-side verification of the PayPal transaction. This makes it possible for unauthenticated attackers to create arbitrary orders on the site with any chosen transaction ID, payment status, prod