The Gutena Forms – Contact Form, Survey Form, Feedback Form, Booking Form, and Custom Form Builder plugin for WordPress is vulnerable to unauthorized modification of data due to missing authorization within the save_gutena_forms_schema() function in all versions up to, and including, 1.6.0. This makes it possible for authenticated attackers, with Contributor-level access and above, to update option values to a structured array value on the WordPress site. This can be leveraged to update an option that would create an error on the site and deny service to legitimate users or be used to set some values, that would, for example enable site user registration when it is explicitly disabled.
