An elevation of privilege vulnerability exists when Microsoft Outlook initiates processing of incoming messages without sufficient validation of the formatting of the messages. An attacker who successfully exploited the vulnerability could attempt to force Outlook to load a local or remote message store (over SMB). To exploit the vulnerability, the attacker could send a specially crafted email to a victim.

Outlook would then attempt to open a pre-configured message store contained in the email upon receipt of the email. This update addresses the vulnerability by ensuring Office fully validates incoming email formatting before processing message content.