The SecuPress Free — WordPress Security plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.2.5.1. This is due to missing or incorrect nonce validation on the secupress_blackhole_ban_ip() function. This makes it possible for unauthenticated attackers to block a user's IP via a forged request granted they can trick the user into performing an action such as clicking on a link.