CVE-2025-52426
📋 TL;DR
A NULL pointer dereference vulnerability in QNAP operating systems allows remote attackers with administrator credentials to cause denial-of-service conditions. This affects QNAP NAS devices running vulnerable QTS and QuTS hero versions. The vulnerability requires administrative access to exploit.
💻 Affected Systems
- QNAP QTS
- QNAP QuTS hero
⚠️ Risk & Real-World Impact
Worst Case
Complete system crash or unavailability of QNAP NAS device, disrupting all services and data access
Likely Case
Temporary service interruption affecting specific QNAP services or applications
If Mitigated
Minimal impact with proper access controls preventing unauthorized administrator access
🎯 Exploit Status
Exploitation requires administrator credentials. The NULL pointer dereference is triggered through specific administrative functions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: QTS 5.2.7.3256 build 20250913 or later, QuTS hero h5.2.7.3256 build 20250913 or later, QuTS hero h5.3.1.3250 build 20250912 or later
Vendor Advisory: https://www.qnap.com/en/security-advisory/qsa-25-50
Restart Required: Yes
Instructions:
1. Log into QNAP web interface as administrator. 2. Go to Control Panel > System > Firmware Update. 3. Check for updates and install the latest firmware version. 4. Reboot the NAS when prompted.
🔧 Temporary Workarounds
Restrict Administrator Access
allLimit administrator account access to trusted IP addresses and users only
Enable Multi-Factor Authentication
allRequire MFA for all administrator accounts to prevent credential compromise
🧯 If You Can't Patch
- Isolate QNAP devices from internet access and restrict to internal network only
- Implement strict access controls and monitoring for administrator account activity
🔍 How to Verify
Check if Vulnerable:
Check QNAP firmware version in Control Panel > System > Firmware UpdateCheck Version:
ssh admin@qnap-ip 'cat /etc/config/uLinux.conf | grep version' or check web interfaceVerify Fix Applied:
Verify firmware version is at or above the patched versions listed in the advisory📡 Detection & Monitoring
Log Indicators:
- Unexpected system crashes or reboots
- Failed authentication attempts for administrator accounts
- NULL pointer error messages in system logs
Network Indicators:
- Unusual administrative access patterns
- Multiple failed login attempts followed by successful admin login
SIEM Query:
source="qnap" AND (event_type="system_crash" OR (auth_result="failure" AND user="admin*") OR message="*NULL pointer*")