The Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder plugin for WordPress is vulnerable to POST-Based Reflected Cross-Site Scripting via the Custom HTML Form parameters in all versions up to, and including, 6.16.1.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE-79

https://plugins.trac.wordpress.org/browser/formidable/tags/6.16/classes/helpers/FrmFieldsHelper.php#L158

https://www.wordfence.com/threat-intel/vulnerabilities/id/da84aa80-7ef6-4846-870d-07bf88652329?source=cve