Vulnerability in Microsoft Windows 11 24h2
CVE-2026-56181
Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
EPSS: 0.003 (19.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.3 (High). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H.
Affected products
- Microsoft Windows_11_24h2
- Microsoft Windows_11_25h2
- Microsoft Windows_11_26h1
- Microsoft Windows 11 Version 24h2 — versions 10.0.26100.0
- Microsoft Windows 11 Version 25h2 — versions 10.0.26200.0
- Microsoft Windows 11 Version 26h1 — versions 10.0.28000.0
- Microsoft Windows Server 2025 — versions 10.0.26100.0
- Microsoft Windows_server_2025
- Microsoft Windows Server 2025 (Server Core Installation) — versions 10.0.26100.0
Weakness classification (CWE)
References
- Windows Network Address Translation (NAT) Spoofing Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-56181?
- CVE-2026-56181 is a high-severity vulnerability in Microsoft Windows 11 24h2, classified under Origin Validation Error. CVSS score: 8.3/10. Published 2026-07-14.
- How severe is CVE-2026-56181?
- High severity. CVSS v3 base score is 8.3 out of 10.