The Joomla component ccBoard 1.1-RC suffers from a Cross Site Scripting vulnerability if certain conditions are met. The forum must be set up to use the internal HTML editor and not bbCode. This is the default setting upon install.

To execute, simply post a new message. Either toggle the editor to 'off' or use the HTML Source editing button, insert your JavaScript, and submit!

<script>alert('xss');</script>

The editor was even nice enough to make my XSS injection pretty upon saving:

<script type="text/javascript">// <![CDATA[
alert('xss');
// ]]></script>