Windows Network Address Translation (NAT)
CVE-2026-56179 — Windows Network Address Translation (NAT) Spoofing Vulnerability
Executive Summary
Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
Overview
8.3
CVSS HIGH
Moderate
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS 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
ATTACK VECTOR
Adjacent_network
ATTACK COMPLEXITY
High
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Changed
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.2
EPSS Score
0.00234
probability of exploitation in the next 30 days
0.14421 percentile - updated 2026-08-14
View on FIRST.org
Affected Products
2 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows 11 Version 24H2 for ARM64-based Systems 5120994 (Security Hotpatch Update) 5121003 (Security Update) Moderate Spoofing 5101650 Base: 8.3 Temporal: 7.2 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 10.0.26100.9106 10.0.26100.9168 Yes None Windows 11 Version 24H2 for x64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Moderate Spoofing 5101650 Base: 8.3 Temporal: 7.2 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 10.0.26100.9168 10.0.26000.9106 Yes None Windows 11 Version 25H2 for ARM64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Moderate Spoofing 5101650 Base: 8.3 Temporal: 7.2 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 10.0.26200.9168 10.0.26100.9106 Yes None Windows 11 Version 25H2 for x64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Moderate Spoofing 5101650 Base: 8.3 Temporal: 7.2 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 10.0.26200.9168 10.0.26100.9106 Yes None Windows 11 Version 26H1 for ARM64-based Systems | 5121000 (Security Update) |
Moderate | Spoofing | Yes |
| Windows 11 version 26H1 for x64-based Systems | 5121000 (Security Update) |
Moderate | Spoofing | Yes |
Patches
1 patch
| Article | Type | Restart |
|---|---|---|
5121000 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
Malcolm Stagg with SODIUM-24, LLC
References
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