Refund Request for WooCommerce <= 1.0 - Missing Authorization to Authenticated (Subscriber+) Refund Status Update

The Refund Request for WooCommerce plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'update_refund_status' function in all versions up to, and including, 1.0. This makes it possible for authenticated attackers, with Subscriber-level access and above, to update refund statuses to approved or rejected.