The WP 2FA – Two-factor authentication for WordPress plugin is vulnerable to a type of cyberattack called Cross-Site Request Forgery. This type of attack is present in all versions up to and including 2.5.0. This vulnerability occurs because the plugin does not always validate a nonce that is associated with the function that sends emails to registered users. This means that attackers can send emails with any content to registered users without needing to authenticate, as long as they can get a site administrator or other registered user to click on a link. The plugin does have a nonce check, but it only works if a nonce is included in the request. Without a nonce, the check can be bypassed.