CVE-2025-53591
📋 TL;DR
A format string vulnerability in QNAP operating systems allows attackers with administrator access to read sensitive data or modify memory. This affects multiple QNAP NAS devices running vulnerable QTS and QuTS hero versions. Remote exploitation requires compromised administrator credentials.
💻 Affected Systems
- QNAP NAS devices
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise through memory corruption leading to arbitrary code execution, data exfiltration, or system modification.
Likely Case
Information disclosure of sensitive system data or limited memory manipulation by attackers with admin access.
If Mitigated
No impact if systems are patched or attackers lack administrator credentials.
🎯 Exploit Status
Exploitation requires administrator credentials and knowledge of format string vulnerabilities
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: QTS 5.2.7.3256 build 20250913, QuTS hero h5.2.7.3256 build 20250913, QuTS hero h5.3.1.3250 build 20250912
Vendor Advisory: https://www.qnap.com/en/security-advisory/qsa-25-50
Restart Required: Yes
Instructions:
1. Log into QNAP web interface as admin. 2. Go to Control Panel > System > Firmware Update. 3. Check for updates and install the latest version. 4. Reboot the NAS after installation.
🔧 Temporary Workarounds
Restrict admin access
allLimit administrator account access to trusted users only and implement strong authentication
Network segmentation
allIsolate QNAP devices from internet and restrict internal network access
🧯 If You Can't Patch
- Implement strict access controls and monitor administrator account activity
- Disable unnecessary services and restrict QNAP device to internal network only
🔍 How to Verify
Check if Vulnerable:
Check current firmware version in Control Panel > System > Firmware UpdateCheck Version:
ssh admin@qnap-ip 'cat /etc/config/uLinux.conf | grep version'Verify Fix Applied:
Verify firmware version matches or exceeds the patched versions listed in the advisory📡 Detection & Monitoring
Log Indicators:
- Unusual administrator login attempts
- Format string error messages in system logs
- Unexpected memory access patterns
Network Indicators:
- Suspicious admin account activity from unusual IPs
- Unexpected format string payloads in network traffic
SIEM Query:
source="qnap_logs" AND (event_type="admin_login" OR message="*format*" OR message="*memory*" OR severity="critical")