Ninja Forms File Uploads <= 3.3.16 - Unauthenticated Stored Cross-Site Scripting via File Upload

The Ninja Forms - File Uploads plugin for WordPress is vulnerable to Stored Cross-Site Scripting via an uploaded file (e.g. RTX file) in all versions up to, and including, 3.3.16 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.