The Country Blocker for AdSense plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.0. This is due to missing nonce validation on the CBFA_guardar_cbfa() function. This makes it possible for unauthenticated attackers to update the plugin's settings via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.