Woo Refund And Exchange Lite < 4.6.4 - Unauthenticated Guest Order Message Disclosure and Manipulation

The Return Refund and Exchange For WooCommerce WordPress plugin before 4.6.4 does not correctly verify the ownership of guest orders in some of the AJAX actions it exposes to unauthenticated users, allowing them to read private order messages, post messages and attachments in the customer's name, and cancel return requests on any guest order.