CVE-2026-56181

EUVD-2026-44316
Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
8.3 HIGH
ADJACENT_NETWORK
HIGH
NONE
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 19.48%
Affected Products (NVD)
VendorProductVersion
microsoftwindows_11_24h2
𝑥
< 10.0.26100.8875
microsoftwindows_11_25h2
𝑥
< 10.0.26200.8875
microsoftwindows_11_26h1
𝑥
< 10.0.28000.2525
microsoftwindows_server_2025
𝑥
< 10.0.26100.33158
𝑥
= Vulnerable software versions
Windows Releases
Platform
Version
Windows 11
24H2 (arm64, x64)
KB5101650
25H2 (arm64, x64)
KB5101650
26H1 (arm64, x64)
KB5101649
Windows Server 2025
Server Core
KB5099536
Standard
KB5099536
Common Weakness Enumeration
References
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56181