The Accept PayPal & Stripe with Subscriptions for WooCommerce WordPress plugin through 3.1.0 does not verify that the PayPal account which received a payment matches the merchant's configured account before marking the order as paid, allowing unauthenticated buyers to complete a WooCommerce order by paying the full amount to their own PayPal account instead of the merchant's.
https://wpscan.com/vulnerability/01cc2578-8bf8-4889-9e21-7b78cae074d7/