WP Crowdfunding <= 2.2.1 - Authenticated (Subscriber+) Stored Cross-Site Scripting via 'first_name' Parameter

The WP Crowdfunding plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'first_name' parameter in all versions up to, and including, 2.2.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. An administrator viewing any user's profile via the ?show_user_id= parameter will render the attacker's stored payload in the admin's browser session, enabling cross-privilege script execution.