A remote code execution vulnerability exists when the Office graphics component improperly handles specially crafted embedded fonts. An attacker who successfully exploited this vulnerability could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
There are multiple ways an attacker could exploit this vulnerability. In a web-based attack scenario, an attacker could host a specially crafted website designed to exploit the vulnerability and then convince a user to view the website. An attacker would have no way to force a user to view the attacker-controlled content. Instead, an attacker would have to convince a user to take action, typically by getting the user to click a link in an email or instant message that takes the user to the attacker's website, or by opening an attachment sent through email.
In a file-sharing attack scenario, an attacker could provide a specially crafted document file designed to exploit the vulnerability and then convince a user to open the document file.
Note that the Preview Pane is not an attack vector for this vulnerability.
The security update addresses the vulnerability by correcting how the Windows font library handles embedded fonts.