Greenshift < 12.9.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Data URI

Description

The Greenshift – animation and page builder blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the customapi action handler in versions up to, and including, 12.8.9. This is due to insufficient sanitization of API responses before output via innerHTML. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses the injected page.