CVE-2026-56181 Windows Network Address Translation (NAT) Spoofing Vulnerability
An attacker can spoof network traffic via Windows NAT origin validation errors, requiring patches for Windows 11 and Server 2025.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56181?
CVE-2026-56181 is a high-severity vulnerability in Microsoft Windows 11 24h2, published on 14 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
Weakness: CWE-346
Which versions are affected by CVE-2026-56181?
It affects 4 products.
Products include Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1, Microsoft Windows Server 2025.
How do I fix CVE-2026-56181?
No fix has been published for CVE-2026-56181 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-56181 being exploited?
There is no known exploitation of CVE-2026-56181 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 11 24h2
- CVE-2025-60710 Microsoft Windows Link Following
- CVE-2026-54990 Remote Desktop Client Remote Code Execution Vulnerability
- CVE-2025-50165 Windows Graphics Component Remote Code Execution Vulnerability
- CVE-2025-21311 Windows NTLM V1 Elevation of Privilege Vulnerability
- CVE-2026-108463 Windows SmartScreen Security Feature Bypass Vulnerability
Sources
Also known as GHSA-q8r6-qhxq-g78g.