Multiple cross-site scripting (XSS) vulnerabilities in DotNetNuke before 3.0.12 allow remote attackers to inject arbitrary web script or HTML via the (1) register a new user page, (2) User-Agent, or (3) Username, which is not properly quoted before sending to the error log.
http://www.woany.co.uk/advisories/dotnetnukexss.txt
http://www.securityfocus.com/bid/13647
http://www.securityfocus.com/bid/13646
http://www.securityfocus.com/bid/13644