Windows NAT Spoofing Vulnerability in Microsoft Products
CVE-2026-56179

8.3HIGH

Key Information:

Vendor

Microsoft
Status
Windows 11 Version 24h2
Windows 11 Version 25h2
Windows 11 Version 26h1
Windows Server 2025
Vendor
CVE Published:
11 August 2026

What is CVE-2026-56179?

An origin validation error in Windows Network Address Translation (NAT) exposes systems to potential spoofing attacks within adjacent networks. This vulnerability could allow unauthorized attackers to impersonate legitimate sources, compromising data integrity and confidentiality. Users are encouraged to apply the latest security updates to mitigate any associated risks.

Affected Version(s)

Windows 11 Version 24H2 ARM64-based Systems 10.0.26100.0 < 10.0.26100.9168

Windows 11 Version 25H2 ARM64-based Systems 10.0.26200.0 < 10.0.26200.9168

Windows 11 version 26H1 ARM64-based Systems 10.0.28000.0 < 10.0.28000.2704

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
8.3
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Adjacent Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.