The CodeColorer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'class' parameter in 'cc' comment shortcode in versions up to, and including, 0.10.1 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. Exploitation requires comments to be enabled on the target post and guest comments to be allowed.