Cross-site scripting (XSS) vulnerability in Horde_Form in Horde Groupware Webmail Edition before 4.0.6 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, related to email verification. NOTE: Some of these details are obtained from third party information.
http://www.openwall.com/lists/oss-security/2012/01/22/2
http://www.horde.org/apps/webmail/docs/RELEASE_NOTES