The Schema & Structured Data for WP & AMP plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the custom schema in all versions up to, and including, 1.26 due to insufficient input sanitization and output escaping. This makes it possible for authenticated malicious users to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. By default the required authentication level is admin, but administrators have the ability to assign role based access to users as low as subscriber.
Vulmon