MultiVendorX < 4.0.26 - Improper Authorization on REST Routes via 'save_settings_permission'

Description

The MultiVendorX plugin for WordPress is vulnerable to unauthorized access of data, modification of data, and loss of data due to an improper capability check on the 'save_settings_permission' function for the REST routes instantiated by the 'mvx_rest_routes_react_module' function versions up to, and including, 4.0.25. This makes it possible for unauthenticated attackers to create, update, and delete vendors, retrieve sensitive information, and modify plugin settings.