The server driver (srv.sys) in Microsoft Windows NT 4.0 2000 XP and Server 2003 allows remote attackers to cause a denial of service (system crash) via an SMB_COM_TRANSACTION SMB message that contains a string without null character termination which leads to a NULL dereference in the ExecuteTransaction function possibly related to an \SMB PIPE \ aka the \Mailslot DOS\ vulnerability. NOTE: the name \Mailslot DOS\ was derived from incomplete initial research; the vulnerability is not associated with a mailslot.