CVE-2025-49689
📋 TL;DR
An integer overflow vulnerability in Virtual Hard Disk (VHDX) handling allows local attackers to escalate privileges on affected systems. This affects Windows systems using VHDX files. Attackers need local access to exploit this vulnerability.
💻 Affected Systems
- Microsoft Windows
📦 What is this software?
Windows 10 1507 by Microsoft
Windows 10 1507 by Microsoft
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 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM/root privileges, allowing installation of malware, data theft, and persistence mechanisms.
Likely Case
Local privilege escalation from standard user to administrator/SYSTEM level, enabling lateral movement and further attacks.
If Mitigated
Limited impact with proper privilege separation and minimal user rights, though local access still poses risk.
🎯 Exploit Status
Requires local access and ability to trigger VHDX operations. No public exploit available yet.
🛠️ 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-2025-49689
Restart Required: Yes
Instructions:
1. Open Windows Update settings
2. Check for updates
3. Install all security updates
4. Restart system when prompted
🔧 Temporary Workarounds
Restrict VHDX Mounting
windowsLimit ability to mount VHDX files to trusted administrators only
User Privilege Reduction
windowsImplement least privilege principle to limit damage from successful exploitation
🧯 If You Can't Patch
- Implement strict access controls and monitor for suspicious VHDX operations
- Segment networks to limit lateral movement if privilege escalation occurs
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for missing security patches related to CVE-2025-49689Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify KB patch number from Microsoft advisory is installed via 'wmic qfe list' or PowerShell 'Get-HotFix'📡 Detection & Monitoring
Log Indicators:
- Unusual VHDX file operations
- Failed privilege escalation attempts
- Suspicious process creation from VHDX-related binaries
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
EventID=4688 OR EventID=4689 with process names containing vhd, disk, or mount operations