The Everest Forms – Contact Form, Quiz, Survey, Newsletter & Payment Form Builder for WordPress plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.1.1 via deserialization of untrusted input from the 'field_value' parameter. This makes it possible for unauthenticated attackers to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.

The The Everest Forms – Contact Form, Quiz, Survey, Newsletter & Payment Form Builder for WordPress plugin for WordPress is vulnerable to arbitrary shortcode execution in all versions up to, and including, 3.1.1. This is due to the software allowing users to execute an action that does not properly validate a value before running do_shortcode. This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary shortcodes.

The Everest Forms – Contact Form, Quiz, Survey, Newsletter & Payment Form Builder for WordPress plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'form_id' parameter in all versions up to, and including, 3.1.1 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.