Pie Register <= 3.8.3.1 - Unauthenticated Arbitrary File Upload

Description The Pie Register plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the pie_save_registration function in versions up to, and including, 3.8.3.1. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site’s server which may make remote code execution possible. NOTE: This vulnerability presents itself when the ‘Anyone can register’ option is enabled in options-general and the ‘Upload File’ field is added to the registration form.