A remote code execution vulnerability exists in the way Microsoft Exchange software parses specially crafted email messages. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the system user. An attacker could then install programs; view, change, add, or delete data. To exploit this vulnerability, an attacker would need to send a specially crafted email to an affected Exchange server, and then convince the recipient to perform multiple actions while replying to the message. The security update addresses the vulnerability by correcting how Microsoft Exchange parses specially crafted email messages.