Vulnerability · Published Aug 11, 2026 · Assigned by microsoft
CVE-2026-56179Windows Network Address Translation (NAT) Spoofing Vulnerability
High 8.3
In plain English
A high-severity security flaw in Windows 11 Version 24H2 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).
Severity (CVSS 3.1)8.3High
Exploit odds (30 days)0.3%top 79.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 – before 10.0.26100.9168 |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 – before 10.0.26200.9168 |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 – before 10.0.28000.2704 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 – before 10.0.26100.33296 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 – before 10.0.26100.33296 |
Weakness: CWE-346 · Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Windows Network Address Translation (NAT) Spoofing Vulnerability vendor-advisory, patch