Advanced Custom Fields (ACF®) <= 6.8.1 - Unauthenticated Arbitrary Post Modification via Front-End Form '_post_title' and '_post_content' Parameters

The Advanced Custom Fields (ACF®) plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 6.8.1. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for unauthenticated attackers to overwrite the post_title and post_content of any post bound to a publicly accessible acf_form() instance by injecting values into the _post_title and _post_content parameters of a form submission request.