PT-2026-58599 · Microsoft · Windows 11 Version 24H2+3

Published 2026-07-14 · Updated 2026-07-14 · CVE-2026-56181

Mitre

CVSS v3.1

8.3

High

Base vector

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

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

Fix

Origin Validation Error

Weakness Enumeration

CWE-346

Related Identifiers

CVE-2026-56181

Affected Products

Windows 11 Version 24H2

Windows 11 Version 25H2

Windows 11 Version 26H1

Windows Server 2025

References · 2

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56181 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-56181 · Security Note