CVE-2025-57711
📋 TL;DR
This vulnerability in Qsync Central allows authenticated administrators to allocate resources without limits, potentially causing denial of service by starving other systems of those same resources. It affects Qsync Central installations before version 5.0.0.4. Organizations using vulnerable versions of Qsync Central for file synchronization are at risk.
💻 Affected Systems
- Qsync Central
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service for Qsync Central and dependent systems, disrupting file synchronization across the organization and potentially affecting business operations.
Likely Case
Degraded performance or temporary service disruption for Qsync Central users, requiring manual intervention to restore normal operations.
If Mitigated
Minimal impact with proper access controls limiting administrator accounts and monitoring resource usage.
🎯 Exploit Status
Exploitation requires administrator credentials but the vulnerability itself is simple to trigger once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Qsync Central 5.0.0.4 (2026/01/20) and later
Vendor Advisory: https://www.qnap.com/en/security-advisory/qsa-26-02
Restart Required: Yes
Instructions:
1. Log into QNAP App Center. 2. Check for updates to Qsync Central. 3. Install version 5.0.0.4 or later. 4. Restart Qsync Central service or the entire NAS if required.
🔧 Temporary Workarounds
Restrict Administrator Access
allLimit the number of administrator accounts and implement strong authentication controls to reduce attack surface.
Implement Resource Monitoring
allMonitor Qsync Central resource usage and set alerts for abnormal consumption patterns.
🧯 If You Can't Patch
- Implement strict access controls on administrator accounts and monitor for suspicious activity
- Isolate Qsync Central to a dedicated network segment and limit which systems can access it
🔍 How to Verify
Check if Vulnerable:
Check Qsync Central version in QNAP App Center or via SSH: cat /etc/config/uLinux.conf | grep qsyncCheck Version:
cat /etc/config/uLinux.conf | grep 'qsync.*version'Verify Fix Applied:
Confirm Qsync Central version is 5.0.0.4 or later in App Center or via version check command📡 Detection & Monitoring
Log Indicators:
- Unusual resource consumption patterns in Qsync Central logs
- Multiple administrator login attempts
- Abnormal file synchronization activity
Network Indicators:
- Increased network traffic to Qsync Central ports
- Unusual connection patterns from administrator accounts
SIEM Query:
source="qnap_logs" AND (process="qsync" AND (resource_usage>threshold OR admin_login=true))