Microsoft Edge (Chromium-based) Security Feature Bypass Vulnerability
CVE-2026-96196
Summary
Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
Products covered
Windows Server 2025 (Server Core installation)
Windows 11 Version 25H2 for ARM64-based Systems
Windows 11 Version 25H2 for x64-based Systems
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows Server 2025
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Remediation
The mitigation is disabled by default. To enable it, apply the following registry keys and reboot the machine. reg add HKLM\SYSTEM\CurrentControlSet\Services\Winnat /v TcpSeqValidation /t REG_DWORD /d 1 /f reg add HKLM\SYSTEM\CurrentControlSet\Services\Winnat /v TcpSeqRandomization /t REG_DWORD /d 1 /f Install KB5120233. Install KB5120228. Install KB5121003. Install KB5120994. Install KB5121000.
Vendor-listed fixes
10.0.26100.33296
10.0.26100.33222
10.0.26200.9168
10.0.26200.9106
10.0.26100.9168
10.0.26100.9106
10.0.28000.2704
CVEs in this advisory 1
Update history
What changed in later vendor updates
SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.
- The vendor changed its remediation guidance.
Updates
- Published by Microsoft Security Response Center
The publication date reported by the vendor.
- Added to SecurityAlert
We collected the advisory from the official source.
- Confirmed at the source
Our collector saw this advisory during a later source check.