Contact Form 7 Extension For Mailchimp <= 0.5.70 is vulnerable to Cross Site Request Forgery (CSRF) vulnerability

The Contact Form 7 Extension For Mailchimp plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 0.5.70. This is due to missing or incorrect nonce validation on a function. This makes it possible for unauthenticated attackers to perform an unauthorized action granted they can trick a site administrator into performing an action such as clicking on a link.