Ninja Forms <= 3.10.2.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via CSTI

The Ninja Forms – The Contact Form Builder That Grows With You plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the use of a templating engine in all versions up to, and including, 3.10.2.1 due to insufficient output escaping on user data passed through the template. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.