The Hustle – Email Marketing, Lead Generation, Optins, Popups plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'content[title]' parameter in all versions up to, and including, 7.8.14.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with custom-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires that an administrator has explicitly granted the 'Create and Update Modules' (hustle_create / hustle_edit_module) capability to the attacker's role via the plugin's own Settings → Permissions feature; this delegation is not enabled by default.