CVE-2026-56179

Windows Network Address Translation (NAT) Spoofing Vulnerability

State: Published
Severity: 8.3 High
Published: Aug 11, 2026
Updated: Oct 30, 2026
Reserved: Jun 19, 2026

Description

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

Scores

CVSS	Score	Vector	Source
3.1	8.3 High	CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-346 Origin Validation Error

Affected Products

Product	Versions
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.9168Affected
Windows 11 Version 25H2Microsoft	10.0.26200.0 to before 10.0.26200.9168Affected
Windows 11 version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.2704Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.33296Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.33296Affected

References

Windows Network Address Translation (NAT) Spoofing Vulnerabilityvendor-advisorypatch

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