The Mailgun for WordPress plugin for WordPress is vulnerable to Server-Side Request Forgery (SSRF) via path traversal in versions up to and including 2.2.0. This is due to insufficient input validation in the add_list() function, which accepts user-controlled array keys from $_POST['addresses'], passes them through sanitize_text_field(). This makes it possible for unauthenticated attackers to make authenticated POST requests to any Mailgun API endpoint using the WordPress site's API key, including creating inbound email-forwarding routes that can intercept password reset emails, leading to administrator account takeover.

The Mailgun for WordPress plugin versions up to and including 2.2.0 is vulnerable to Server-Side Request Forgery (SSRF) via path traversal. The vulnerability exists in the add_list() function due to insufficient input validation of user-controlled array keys from $_POST['addresses'], which are only passed through sanitize_text_field() before use. Unauthenticated attackers can exploit this flaw to make authenticated POST requests to any Mailgun API endpoint using the WordPress site's stored API key. This can be leveraged to create inbound email-forwarding routes that intercept password reset emails. Successful exploitation can lead to full administrator account takeover. No authentication is required to exploit this vulnerability, making it particularly dangerous for any site running the affected plugin versions.