Envo Extra <= 1.8.23 - Authenticated (Contributor+) Stored Cross-Site Scripting via Button Widget

The Envo Extra plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘button_css_id’ parameter within the Button widget in all versions up to, and including, 1.8.23 due to insufficient input sanitization and output escaping. 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 an injected page.