The Jupiter X Core plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'fields[<custom_meta_field_id>]' parameter in all versions up to, and including, 4.62.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Execution requires that the attacker-registered account be assigned as the post_author of a page or post whose template includes the Raven Author Box widget, a fixture an administrator can create by reassigning authorship to any user including newly registered Subscribers.