Ninja Forms - File Uploads Extension <= 3.3.0 - Arbitrary File Upload

The Ninja Forms - File Uploads Extension WordPress plugin is vulnerable to arbitrary file uploads due to insufficient input file type validation found in the ~/includes/ajax/controllers/uploads.php file which can be bypassed making it possible for unauthenticated attackers to upload malicious files that can be used to obtain remote code execution, in versions up to and including 3.3.0