The Two-factor authentication (formerly IP Vault) plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.1. This is due to missing or incorrect nonce validation on the ipv_save_changes function. This makes it possible for unauthenticated attackers to modify the plugin's firewall and two-factor authentication settings — including the operating mode, request include/exclude rules, authentication slug, and log retention period — potentially disabling protection entirely via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.