Pie Register - Basic <= 3.8.3.4 - Missing Authorization to Authenticated (Subscriber+) Arbitrary Plugin Installation

The Registration Forms – User Registration Forms, Invitation-Based Registrations, Front-end User Profile, Login Form & Content Restriction plugin for WordPress is vulnerable to unauthorized arbitrary plugin installation due to a missing capability check on the pieregister_install_addon function in all versions up to, and including, 3.8.3.4. This makes it possible for authenticated attackers, with subscriber-level access and above, to install arbitrary plugins. As a result attackers might achieve code execution on the targeted server