Microsoft Distributed Transaction Coordinator (MSDTC) for Windows NT 4.0, 2000 SP4, XP SP1 and SP2, and Server 2003 allows remote attackers to cause a denial of service (crash) via a BuildContextW request with a large (1) UuidString or (2) GuidIn of a certain length, which causes an out-of-range memory access, aka the MSDTC Denial of Service Vulnerability.  NOTE: this is a variant of CVE-2005-2119.