CVE intelligence

CVE-2026-56179

Vulnerability intelligence

Published Aug 11, 2026Sources checked Oct 28, 2026

8.3HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-56179 and is rated High severity with a CVSS score of 8.3. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Aug 11, 2026

Vendor remediation details

The mitigation is disabled by default. To enable it, apply the following registry keys and reboot the machine. reg add HKLM\SYSTEM\CurrentControlSet\Services\Winnat /v TcpSeqValidation /t REG_DWORD /d 1 /f reg add HKLM\SYSTEM\CurrentControlSet\Services\Winnat /v TcpSeqRandomization /t REG_DWORD /d 1 /f Install KB5120233. Install KB5120228. Install KB5121003. Install KB5120994. Install KB5121000.

Vendor-listed releases

10.0.26100.33296
10.0.26100.33222
10.0.26200.9168
10.0.26200.9106
10.0.26100.9168
10.0.26100.9106
10.0.28000.2704

CISA KEVNot listedBased on the latest collected catalog

EPSS0.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-56179?

Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.

Source: NVD