Microsoft Outlook and Outlook Express allow remote attackers to cause a denial of service by sending email messages with blank fields such as BCC, Reply-To, Return-Path, or From.

Microsoft Outlook client allows remote attackers to cause a denial of service by sending multiple email messages with the same X-UIDL headers, which causes Outlook to hang.

The Microsoft Outlook mail client identifies the physical path of the sender's machine within a winmail.dat attachment to Rich Text Format (RTF) files.

Microsoft Outlook 98 and 2000, and Outlook Express 4.0x and 5.0x, allow remote attackers to read files on the client's system via a malformed HTML message that stores files outside of the cache, aka the "Cache Bypass" vulnerability.

Buffer overflow in Microsoft Outlook and Outlook Express allows remote attackers to execute arbitrary commands via a long Date field in an email header, aka the "Malformed E-mail Header" vulnerability.

Microsoft Outlook 8.5 and earlier, and Outlook Express 5 and earlier, with the "Automatically put people I reply to in my address book" option enabled, do not notify the user when the "Reply-To" address is different than the "From" address, which could allow an untrusted remote attacker to spoof legitimate addresses and intercept email from the client that is intended for another user.

Unknown versions of Internet Explorer and Outlook allow remote attackers to spoof a legitimate URL in the status bar via A HREF tags with modified "alt" values that point to the legitimate site, combined with an image map whose href points to the malicious site, which facilitates a "phishing" attack.