Ninja Forms - File Uploads Extension <= 3.3.12 - Reflected Cross-Site Scripting

The Ninja Forms - File Uploads Extension WordPress plugin is vulnerable to reflected cross-site scripting due to missing sanitization of the files filename parameter found in the ~/includes/ajax/controllers/uploads.php file which can be used by unauthenticated attackers to add malicious web scripts to vulnerable WordPress sites, in versions up to and including 3.3.12.