Cross-site scripting (XSS) vulnerability in index.php in phplist before 2.10.3 allows remote attackers to inject arbitrary web script or HTML via the unsubscribeemail parameter.
http://www.vupen.com/english/advisories/2006/4027
http://www.securityfocus.com/archive/1/448411/100/0/threaded
http://websecurity.com.ua/267/
http://securityreason.com/securityalert/1728