The Multi Step Form plugin for WordPress is vulnerable to unauthorized limited file upload due to a missing capability check on the fw_upload_file AJAX action in all versions up to, and including, 1.7.23. This makes it possible for unauthenticated attackers to upload limited file types such as images.
Missing Authorization vulnerability in mondula2016 Multi Step Form multi-step-form allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Multi Step Form: from n/a through <= 1.7.21.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Mondula GmbH Multi Step Form allows Stored XSS.This issue affects Multi Step Form: from n/a through 1.7.13.
The Multi Step Form WordPress plugin before 1.7.8 does not sanitise and escape some of its form fields, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).
The Mondula Multi Step Form plugin through 1.2.5 for WordPress allows XSS via the fw_data [id][1], fw_data [id][2], fw_data [id][3], fw_data [id][4], or email field of the contact form, exploitable with an fw_send_email action to wp-admin/admin-ajax.php.