The U.S. software weapon would have allowed the spy agency’s hackers to break into potentially millions of Windows computers by exploiting a flaw in how certain versions of Windows implemented a network protocol commonly used to share files and to print.

Source: Leaked NSA Malware Is Helping Hijack Computers Around the World

From:  Security Update for Microsoft Windows SMB Server (4013389)

This security update resolves vulnerabilities in Microsoft Edge. The most severe of the vulnerabilities could allow remote code execution if a user views a specially crafted webpage using Microsoft Edge. An attacker who successfully exploited these vulnerabilities could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.