Integer overflow in the CryptoAPI component 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 allows man-in-the-middle attackers to spoof arbitrary SSL servers and other entities via an X.509 certificate that has a malformed ASN.1 Object Identifier (OID) and was issued by a legitimate Certification Authority, aka "Integer Overflow in X.509 Object Identifiers Vulnerability."