The Windows Live Hotmail PUSH mail (aka com.clearhub.wl) application 1.00.97 for Android does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

Integer overflow in inetcomm.dll in Microsoft Outlook Express 5.5 SP2, 6, and 6 SP1; Windows Live Mail on Windows XP SP2 and SP3, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7; and Windows Mail on Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7 allows remote e-mail servers and man-in-the-middle attackers to execute arbitrary code via a crafted (1) POP3 or (2) IMAP response, as demonstrated by a certain +OK response on TCP port 110, aka "Outlook Express and Windows Mail Integer Overflow Vulnerability."

Microsoft Crypto API 5.131.2600.2180 through 6.0, as used in Outlook, Windows Live Mail, and Office 2007, performs Certificate Revocation List (CRL) checks by using an arbitrary URL from a certificate embedded in a (1) S/MIME e-mail message or (2) signed document, which allows remote attackers to obtain reading times and IP addresses of recipients, and port-scan results, via a crafted certificate with an Authority Information Access (AIA) extension.