This security update resolves vulnerabilities in Microsoft Windows, Microsoft Office, Skype for Business, Microsoft Lync, and Microsoft Silverlight. The most severe of these vulnerabilities could allow remote code execution if a user either visits a specially crafted website or opens a specially crafted document. 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.

https://technet.microsoft.com/en-us/library/security/MS17-013