CVE-2026-56179

Published: Aug 11, 2026Modified: Aug 13, 2026

8.3

Vector

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploitability: 1.6 / Impact: 6.0

Source: secure@microsoft.com (Secondary)

Description

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

Affected (7)

Products: Microsoft: Windows 11 24h2, Windows 11 25h2, Windows 11 26h1, Windows Server 2025

4 products

Windows 11 24h2

Windows 11 25h2

Windows 11 26h1

Windows Server 2025

Configuration A

7 vulnerable

Vulnerable Software	Affected Versions
Microsoft Windows 11 24h2	Before 10.0.26100.9106
Microsoft Windows 11 24h2	Before 10.0.26100.9106
Microsoft Windows 11 25h2	Before 10.0.26200.9106
Microsoft Windows 11 25h2	Before 10.0.26200.9106
Microsoft Windows 11 26h1	Before 10.0.28000.2704
Microsoft Windows 11 26h1	Before 10.0.28000.2704
Microsoft Windows Server 2025	Before 10.0.26100.33222

Related CWEs

Origin Validation Error

The product does not properly verify that the source of data or communication is valid.

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56179

Source: secure@microsoft.com

PatchVendor Advisory

Timeline

No history available yet.