WP Categories Widget <= 2.2 is vulnerable to Cross Site Scripting (XSS) vulnerability

The WP Categories Widget plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via several parameters in the wcw_terms_list() function called via an AJAX action in versions up to, and including, 2.2 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.