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Vulnerability record · public intelligence
CVE-2020-16899
HIGH

Windows TCP/IP Denial of Service Vulnerability

Published Oct 16, 2020 · Updated Oct 23, 2026

Severity · CVSSHIGH · 7.5
Known exploitationNot listed
EPSS / likelihood13.45%
QFinch risk score10 / 100

Original summary

Normalized public record · Updated Oct 23, 2026

Windows TCP/IP Denial of Service Vulnerability

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

<p>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.</p> <p>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.</p> <p>The update addresses the vulnerability by correcting how the Windows TCP/IP stack handles ICMPv6 Router Advertisement packets.</p>

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

CVENVDEPSS
SSVC priority
MEDIUM
Confidence
10%
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. portal.msrc.microsoft.com ↗

Record history

Published Oct 16, 2020 · Last refreshed Oct 23, 2026