Microsoft CVE-2018-8310: Microsoft Office Tampering Vulnerability

A tampering vulnerability exists when Microsoft Outlook does not properly handle specific attachment types when rendering HTML emails. An attacker could exploit the vulnerability by sending a specially crafted email and attachment to a victim, or by hosting a malicious .eml file on a web server.
The attacker who successfully exploited the vulnerability could then embed untrusted TrueType fonts in the body of an email. This behavior could be combined with other exploits to further compromise a user's system.
The security update addresses the vulnerability by correcting how Microsoft Outlook handles attachments.