CF7 Invisible reCAPTCHA <= 1.3.3 - Cross-Site Request Forgery via vsz_cf7_invisible_recaptcha_page

The CF7 Invisible reCAPTCHA plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 1.3.3. This is due to missing nonce validation on the vsz_cf7_invisible_recaptcha_page() function. This makes it possible for unauthenticated attackers to modify 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.