The SMB client in the kernel in Microsoft Windows Server 2008 R2 and Windows 7 allows remote SMB servers and man-in-the-middle attackers to cause a denial of service (infinite loop and system hang) via a (1) SMBv1 or (2) SMBv2 response packet that contains (a) an incorrect length value in a NetBIOS header or (b) an additional length field at the end of this response packet, aka "SMB Client Incomplete Response Vulnerability."