CVE-2026-20936
📋 TL;DR
This vulnerability is an out-of-bounds read in Windows NDIS (Network Driver Interface Specification) that allows an authorized attacker with physical access to potentially disclose sensitive information from kernel memory. It affects Windows systems with vulnerable NDIS implementations, requiring the attacker to have local access to the target machine.
💻 Affected Systems
- Windows operating systems
📦 What is this software?
Windows 10 1607 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
Windows 11 24h2 by Microsoft
Windows 11 25h2 by Microsoft
Windows 11 25h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
An attacker with physical access could read kernel memory contents, potentially exposing sensitive data like passwords, encryption keys, or other system information that could facilitate further attacks.
Likely Case
Information disclosure of limited kernel memory contents, potentially revealing system state information but unlikely to lead to full system compromise without additional vulnerabilities.
If Mitigated
With proper physical security controls and up-to-date patching, the risk is minimal as the attacker requires physical access and authorization.
🎯 Exploit Status
Exploitation requires physical access and authorization, making it less likely to be widely weaponized compared to remote vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific patch versions
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20936
Restart Required: Yes
Instructions:
1. Visit Microsoft Security Update Guide for CVE-2026-20936
2. Download the appropriate security update for your Windows version
3. Install the update following Microsoft's instructions
4. Restart the system as required
🔧 Temporary Workarounds
Physical Security Controls
allImplement strict physical access controls to prevent unauthorized physical access to systems
Principle of Least Privilege
windowsLimit user privileges to reduce the attack surface from authorized users
🧯 If You Can't Patch
- Implement strict physical security controls and access monitoring
- Apply network segmentation and limit physical access to sensitive systems
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for the specific security update mentioned in Microsoft's advisory for CVE-2026-20936Check Version:
wmic os get caption, version, buildnumberVerify Fix Applied:
Verify the security update is installed via Windows Update history or by checking system version against patched versions in Microsoft's advisory📡 Detection & Monitoring
Log Indicators:
- Unusual physical access logs
- Suspicious driver or kernel module activity
Network Indicators:
- Not applicable - this is a local physical attack
SIEM Query:
Not applicable for network detection as this requires physical access