CVE-2020-16899: Microsoft Windows 10

High severity, CVSS 7.5. EPSS: 13.5% chance of exploitation in the next 30 days.

A denial of service vulnerability exists when the Windows TCP/IP stack improperly handles ICMPv6 Router Advertisement packets. An attacker who successfully exploited this vulnerability could cause a target system to stop responding. To exploit this vulnerability, an attacker would have to send specially crafted ICMPv6 Router Advertisement packets to a remote Windows computer. The vulnerability would not allow an attacker to execute code or to elevate user rights directly. The update addresses the vulnerability by correcting how the Windows TCP/IP stack handles ICMPv6 Router Advertisement packets.

Affected products

Microsoft Windows 10: version 1709 only; version 1803 only; version 1809 only; version 1903 only; version 1909 only; version 2004 only
Microsoft Windows Server 2016: version 1903 only; version 1909 only; version 2004 only
Microsoft Windows Server 2019: affected versions not specified

Published 2020-10-16. Last modified 2026-06-17.