WPForms 1.8.4 - 1.9.2.1 - Missing Authorization to Authenticated (Subscriber+) Payment Refund and Subscription Cancellation

Description

The WPForms plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'wpforms_is_admin_page' function in versions starting from 1.8.4 up to, and including, 1.9.2.1. This makes it possible for authenticated attackers, with Subscriber-level access and above, to refund payments and cancel subscriptions.