Input validation

The SMB Server in Microsoft Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7 does not properly validate an internal variable in an SMB packet, which allows remote attackers to cause a denial of service (system hang) via a crafted (1) SMBv1 or (2) SMBv2 packet, aka “SMB Variable Validation Vulnerability.”