The Narrative Publisher WordPress plugin through 1.0.7 does not restrict write access to a REST-exposed post meta field or escape it when rendering, allowing users with contributor-level access and above to store JavaScript that executes in the browser of any higher-privileged user who views the affected post.
https://wpscan.com/vulnerability/c98113a9-ee8a-4a24-8b2f-d506b99bba1c/