The WOOCS WordPress plugin before 1.3.7.3 does not sanitise and escape the custom_prices parameter before outputting it back in the response, leading to a Reflected Cross-Site Scripting issue
https://wpscan.com/vulnerability/8601bd21-becf-4809-8c11-d053d1121eae
https://plugins.trac.wordpress.org/changeset/2640621/woocommerce-currency-switcher