The Everest Forms plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 3.4.4. This is due to the loadpreviousfieldvalue() method in class-evf-form-task.php accepting arbitrary URL values from $POST data for upload fields without domain restriction, which are then passed to wpremotehead() in the getlocalfilesize() method of class-evf-form-fields-upload.php. This makes it possible for unauthenticated attackers to force the WordPress server to make outbound HTTP HEAD requests to arbitrary URLs by submitting a form with an upload field containing a malicious URL while leaving a required field empty to trigger form re-rendering.

The Everest Forms WordPress plugin before 3.5.0 does not reliably delete temporary CSV files generated during email-notification processing and leaves them publicly accessible in the uploads directory, allowing unauthenticated attackers to retrieve other users' form submission records via predictable, enumerable filenames.

The Everest Forms WordPress plugin before 3.5.0 does not correctly restrict access to several REST API endpoints belonging to its onboarding assistant: the capability check is only applied when an attacker-controllable request header holds a specific value, so it can be bypassed by omitting or changing that header. This makes it possible for unauthenticated attackers to read onboarding status information, modify the related Everest Forms WordPress plugin before 3.5.0 options, and trigger an email from the site to an arbitrary address.

The Everest Forms plugin for WordPress is vulnerable to Arbitrary File Read and Deletion in all versions up to, and including, 3.4.4. This is due to the plugin trusting attacker-controlled oldfiles data from public form submissions as legitimate server-side upload state, and converting attacker-supplied URLs into local filesystem paths using regex-based string replacement without canonicalization or directory boundary enforcement. This makes it possible for unauthenticated attackers to read arbitrary local files (e.g., wp-config.php) by injecting path-traversal payloads into the oldfiles upload field parameter, which are then attached to notification emails. The same path resolution is also used in the post-email cleanup routine, which calls unlink() on the resolved path, resulting in the targeted file being deleted after being attached. This can lead to full site compromise through disclosure of database credentials and authentication salts from wp-config.php, and denial of service through deletion of critical files. Prerequisite: The form must contain a file-upload or image-upload field, and disable storing entry information.

The Everest Forms plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 2.0.7 via the 'fonturl' parameter. This makes it possible for unauthenticated attackers to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.

The Everest Forms (Pro) plugin for WordPress is vulnerable to arbitrary file deletion due to insufficient file path validation in the deleteentryfiles() function in all versions up to, and including, 1.9.4. This makes it possible for unauthenticated attackers to delete arbitrary files on the server, which can easily lead to remote code execution when the right file is deleted (such as wp-config.php). The vulnerability requires an admin to trigger the deletion via deletion of a form entry and cannot be carried out by the attacker alone.

The Everest Forms – Contact Forms, Quiz, Survey, Newsletter & Payment Form Builder for WordPress plugin for WordPress is vulnerable to arbitrary file upload, read, and deletion due to missing file type and path validation in the 'format' method of the EVFFormFieldsUpload class in all versions up to, and including, 3.0.9.4. This makes it possible for unauthenticated attackers to upload, read, and delete arbitrary files on the affected site's server which may make remote code execution, sensitive information disclosure, or a site takeover possible.

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 doshortcode. 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 PHP Object Injection in all versions up to, and including, 3.1.1 via deserialization of untrusted input from the 'fieldvalue' 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 Everest Forms WordPress plugin before 3.0.3.1 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfilteredhtml capability is disallowed (for example in multisite setup).

The Everest Forms WordPress plugin before 3.0.8.1 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfilteredhtml capability is disallowed (for example in multisite setup).

The Everest Forms WordPress plugin before 3.0.4.2 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfilteredhtml capability is disallowed (for example in multisite setup).