CVE-2025-27490
📋 TL;DR
A heap-based buffer overflow vulnerability in Windows Bluetooth Service allows authenticated attackers to execute arbitrary code with elevated SYSTEM privileges. This affects Windows systems with Bluetooth functionality enabled. Attackers must already have local access to exploit this vulnerability.
💻 Affected Systems
- Windows Bluetooth Service
📦 What is this software?
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 privileges leading to persistent backdoors, credential theft, and lateral movement across the network.
Likely Case
Privilege escalation from standard user to SYSTEM, enabling installation of malware, disabling security controls, and accessing sensitive system resources.
If Mitigated
Limited impact with proper network segmentation, endpoint protection, and least privilege principles in place.
🎯 Exploit Status
Requires authenticated access and knowledge of heap manipulation techniques. No public exploits 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-2025-27490
Restart Required: Yes
Instructions:
1. Open Windows Update Settings
2. Click 'Check for updates'
3. Install all available security updates
4. Restart system when prompted
🔧 Temporary Workarounds
Disable Bluetooth Service
windowsTemporarily disable Bluetooth functionality to prevent exploitation
sc config bthserv start= disabled
sc stop bthserv
Remove Bluetooth Permissions
windowsRestrict standard user access to Bluetooth service
icacls "C:\Windows\System32\bthserv.exe" /deny Users:(RX)
🧯 If You Can't Patch
- Implement strict network segmentation to limit lateral movement
- Deploy endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check if Bluetooth service is running and system has not applied the latest Windows security updatesCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history shows successful installation of the relevant security update📡 Detection & Monitoring
Log Indicators:
- Event ID 4688 with parent process bthserv.exe
- Unexpected privilege escalation from standard user to SYSTEM
- Abnormal Bluetooth service crashes
Network Indicators:
- Unusual Bluetooth connection attempts from non-standard devices
- Lateral movement attempts following local privilege escalation
SIEM Query:
source="windows" (event_id=4688 AND parent_process_name="bthserv.exe") OR (event_id=4672 AND subject_user_name!="SYSTEM" AND target_user_name="SYSTEM")