Cross-site scripting (XSS) vulnerability in piCal 0.91h and earlier, a module for XOOPS, allows remote attackers to inject arbitrary web script or HTML via the event_id parameter in index.php.
http://xoops.peak.ne.jp/md/news/index.php?page=article&storyid=476&easiestml_lang=xlang%3Aen
http://xoops.peak.ne.jp/md/news/
http://www.securityfocus.com/bid/33896
http://secunia.com/advisories/33986