The Key Distribution Center (KDC) in Kerberos in Microsoft Windows 2000 SP4 Server 2003 SP2 and Server 2008 Gold and SP2 when a trust relationship with a non-Windows Kerberos realm exists allows remote authenticated users to cause a denial of service (NULL pointer dereference and domain controller outage) via a crafted Ticket Granting Ticket (TGT) renewal request aka \Kerberos Null Pointer Dereference Vulnerability.\