Citrix MetaFrame up to XP 1.0 Feature 1, except when running on Windows Server 2003, installs a registry key with an insecure ACL, which allows remote authenticated users to gain privileges.
Citrix MetaFrame 1.8 Server with Service Pack 3, and XP Server Service Pack 1 and earlier, allows remote attackers to cause a denial of service (crash) via a large number of incomplete connections to the server.
CITRIX Metaframe 1.8 logs the Client Address (IP address) that is provided by the client instead of obtaining it from the packet headers, which allows clients to spoof their public IP address, e.g. through Network Address Translation (NAT).