CVE-2026-20922
📋 TL;DR
A heap-based buffer overflow vulnerability in Windows NTFS allows authenticated attackers to execute arbitrary code locally on affected systems. This affects Windows systems with NTFS file systems where an attacker has local access. The vulnerability could lead to privilege escalation or system compromise.
💻 Affected Systems
- Windows NTFS
📦 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 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
Windows 11 25h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with SYSTEM privileges, allowing complete control over the affected machine, data theft, and lateral movement within the network.
Likely Case
Privilege escalation from standard user to administrator/SYSTEM level, enabling installation of malware, persistence mechanisms, or credential harvesting.
If Mitigated
Limited impact with proper privilege separation and application control policies in place, potentially resulting in application crashes rather than code execution.
🎯 Exploit Status
Requires authenticated access and specific conditions to trigger the buffer overflow. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific KB numbers
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20922
Restart Required: Yes
Instructions:
1. Apply latest Windows security updates from Microsoft Update. 2. For enterprise environments, deploy patches through WSUS or SCCM. 3. Restart affected systems after patch installation.
🔧 Temporary Workarounds
Restrict local user privileges
windowsLimit standard user privileges to reduce attack surface
Implement application control policies
windowsUse AppLocker or Windows Defender Application Control to restrict unauthorized code execution
🧯 If You Can't Patch
- Implement strict least privilege access controls for all user accounts
- Monitor for suspicious process creation and privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for missing security patches related to CVE-2026-20922Check Version:
wmic os get caption, version, buildnumberVerify Fix Applied:
Verify patch installation through Windows Update history or by checking system version against patched versions📡 Detection & Monitoring
Log Indicators:
- Unexpected process creation with elevated privileges
- Application crashes related to ntfs.sys or file system operations
- Security event ID 4688 with unusual parent processes
Network Indicators:
- No direct network indicators - local exploitation only
SIEM Query:
EventID=4688 AND (NewProcessName contains "cmd.exe" OR NewProcessName contains "powershell.exe") AND SubjectUserName NOT IN ("SYSTEM", "NETWORK SERVICE", "LOCAL SERVICE")