The SMB client in Microsoft Windows 2000 SP4, Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista Gold, SP1, and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7 does not properly allocate memory for SMB responses, which allows remote SMB servers and man-in-the-middle attackers to execute arbitrary code via a crafted (1) SMBv1 or (2) SMBv2 response, aka "SMB Client Memory Allocation Vulnerability."