WP GoToWebinar <= 15.7 - Cross-Site Request Forgery to Stored Cross-Site Scripting

The WP GoToWebinar plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 15.7. This is due to missing or incorrect nonce validation on the wp_gotowebinar_save_authentication_details() function. This makes it possible for unauthenticated attackers to inject malicious web scripts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.