The Mailchimp List Subscribe Form plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.0.0. This is due to missing or incorrect nonce validation on the mailchimp_sf_change_list_if_necessary() function. This makes it possible for unauthenticated attackers to change Mailchimp lists via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

The Mailchimp for WooCommerce WordPress plugin before 2.7.2 has an AJAX action that allows high privilege users to perform a POST request on behalf of the server to the internal network/LAN, the body of the request is also appended to the response so it can be used to scan private network for example

The Mailchimp for WooCommerce WordPress plugin before 2.7.1 has an AJAX action that allows any logged in users (such as subscriber) to perform a POST request on behalf of the server to the internal network/LAN, the body of the request is also appended to the response so it can be used to scan private network for example

Cross-site scripting (XSS) vulnerability in the Easy MailChimp Forms plugin 3.0 through 5.0.6 for WordPress allows remote attackers to inject arbitrary web script or HTML via the update_options action to wp-admin/admin-ajax.php.