Paid Memberships Pro < 3.0.5 - Unauthenticated Insecure Direct Object Reference to Order Status Update

Description

The Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 3.0.4 via the pmpro_twocheckoutValidate function due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to update an order status to paid.