CVE-2025-53716
📋 TL;DR
A null pointer dereference vulnerability in Windows LSASS allows authenticated attackers to cause a denial of service by crashing the service. This affects Windows systems where LSASS is running, potentially disrupting authentication and security policy enforcement. Only authorized users can exploit this vulnerability.
💻 Affected Systems
- Windows Local Security Authority Subsystem Service (LSASS)
📦 What is this software?
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
LSASS crashes, causing authentication failures, security policy enforcement disruption, and requiring system reboot to restore functionality.
Likely Case
Temporary denial of service affecting authentication and security operations until LSASS restarts or system reboots.
If Mitigated
Minimal impact with proper access controls limiting who can trigger the vulnerability.
🎯 Exploit Status
Requires authenticated access and specific conditions to trigger the null pointer dereference.
🛠️ 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-2025-53716
Restart Required: No
Instructions:
1. Apply Windows Update from Microsoft. 2. Install the specific security update for your Windows version. 3. Verify LSASS is running normally after update.
🔧 Temporary Workarounds
Restrict LSASS access
WindowsLimit which users and processes can interact with LSASS through security policies
Use Group Policy or local security policy to restrict LSASS access
🧯 If You Can't Patch
- Implement strict access controls to limit who can interact with LSASS
- Monitor LSASS process health and restart automatically if crashes occur
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for the specific security update or use Microsoft's security update verification toolsCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify the security update is installed and LSASS is running without issues📡 Detection & Monitoring
Log Indicators:
- Event ID 1000 or similar application crash events for lsass.exe
- Unexpected LSASS restarts in system logs
Network Indicators:
- Authentication failures following LSASS crash
- Increased failed login attempts
SIEM Query:
EventID=1000 AND ProcessName="lsass.exe" OR EventID=4625 following lsass crash