The Payment Gateway for Redsys & WooCommerce Lite WordPress plugin before 7.0.2 does not verify the authenticity of incoming payment-provider notifications for one of its payment methods before marking orders as paid, allowing unauthenticated attackers to forge a payment-confirmation callback and complete their own orders without paying.
https://wpscan.com/vulnerability/1ff08062-8f2c-4542-b795-fe82bfa6040c/