Input validation vulnerability in ChillPay WooCommerce 2.5.3

The ChillPay plugin for WordPress, called WooCommerce, has a security issue in all versions up to 2.5.3. This is because it does not properly check for authentication when a certain function is used. This means that someone who is not logged in can change the settings and add harmful code to the website by fooling the site administrator into doing something, like clicking on a link.