srv.sys in the Server service in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, and Server 2008 allows remote attackers to cause a denial of service (system crash) or possibly have unspecified other impact via an SMB WRITE_ANDX packet with an offset that is inconsistent with the packet size, related to "insufficiently validating the buffer size," as demonstrated by a request to the PIPElsarpc named pipe, aka "SMB Validation Denial of Service Vulnerability."