CVE-2020-16899 — Windows TCP/IP Denial of Service Vulnerability

Executive Summary

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.

Overview

7.5

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

More Likely

MS Exploit Likelihood

Category Denial of Service

Released Oct 13 2020

Last Updated Oct 13 2020

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.13348 — 0.96004 percentile

NVD CVSS 7.5 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

None

INTEGRITY

None

AVAILABILITY

High

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 6.7

EPSS Score

0.13348

probability of exploitation in the next 30 days

0.96004 percentile - updated 2026-07-25

View on FIRST.org

Affected Products

23 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1709 for 32-bit Systems	`4580328 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1709 for ARM64-based Systems	`4580328 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1709 for x64-based Systems	`4580328 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1803 for 32-bit Systems	`4580330 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1803 for ARM64-based Systems	`4580330 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1803 for x64-based Systems	`4580330 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1809 for 32-bit Systems	`4577668 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1809 for ARM64-based Systems	`4577668 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1809 for x64-based Systems	`4577668 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1903 for 32-bit Systems	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1903 for ARM64-based Systems	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1903 for x64-based Systems	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1909 for 32-bit Systems	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1909 for ARM64-based Systems	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 1909 for x64-based Systems	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 2004 for 32-bit Systems	`4579311 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 2004 for ARM64-based Systems	`4579311 (Security Update)`	Important	Denial of Service	Yes
Windows 10 Version 2004 for x64-based Systems	`4579311 (Security Update)`	Important	Denial of Service	Yes
Windows Server 2019	`4577668 (Security Update)`	Important	Denial of Service	Yes
Windows Server 2019 (Server Core installation)	`4577668 (Security Update)`	Important	Denial of Service	Yes
Windows Server, version 1903 (Server Core installation)	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows Server, version 1909 (Server Core installation)	`4577671 (Security Update)`	Important	Denial of Service	Yes
Windows Server, version 2004 (Server Core installation)	`4579311 (Security Update)`	Important	Denial of Service	Yes

Patches

5 patches

Article	Type	Restart
`4580328`	Security Update	Yes
`4580330`	Security Update	Yes
`4577668`	Security Update	Yes
`4577671`	Security Update	Yes
`4579311`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Microsoft Platform Security Assurance & Vulnerability Research

References

MSRC Advisory MITRE NVD