The Formidable Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via multiple parameters submitted during form entries like 'afterhtml' in versions before 2.05.03 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute in a victim's browser.

The Formidable Kinetic plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'kineticlink' shortcode in versions up to, and including, 1.1.01. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes (notably 'window', 'class', and 'label') in the FrmKinetic::link() function, which are concatenated directly into HTML attributes of an anchor tag. 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.

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.

The Formidable Forms WordPress plugin before 6.32.1 does not properly validate the status of a PayPal subscription payment before marking it complete, allowing unauthenticated users to bypass payment and trigger paid form actions — such as digital content access, license delivery, and membership activation — without being charged.

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.