The Formidable Form Builder WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization found in the ~/classes/helpers/FrmAppHelper.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 5.0.06. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.
