Cross-Site Request Forgery Vulnerability in Schema App Structured Data Plugin for WordPress

Summary

The Schema App Structured Data plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.2.0. This is due to missing or incorrect nonce validation on the MarkUpdate function. This makes it possible for unauthenticated attackers to update and delete post metadata via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.