Spoofing Vulnerability in Windows Network Address Translation by Microsoft
CVE-2026-56181

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:
14 July 2026

What is CVE-2026-56181?

A vulnerability exists in the Windows Network Address Translation (NAT) system due to an origin validation error, enabling unauthorized attackers to execute spoofing attacks within adjacent networks. This susceptible scenario could lead to significant security risks and compromise the integrity of network communications.

Affected Version(s)

Windows 11 Version 24H2 ARM64-based Systems 10.0.26100.0 < 10.0.26100.8875

Windows 11 Version 25H2 ARM64-based Systems 10.0.26200.0 < 10.0.26100.8875

Windows 11 version 26H1 ARM64-based Systems 10.0.28000.0 < 10.0.28000.2525

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

.