Formidable Forms <= 6.11.1 - Authenticated (Subscriber+) Stored Cross-Site Scripting

The Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘html’ parameter in all versions up to, and including, 6.11.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with form editing permissions and Subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.