CVE-2025-54149 Overview
An uncontrolled resource consumption vulnerability has been identified in QNAP Qsync Central, a file synchronization application for QNAP NAS devices. This vulnerability allows a local attacker who has gained access to a user account to exploit the flaw and launch a denial-of-service (DoS) attack against the affected system.
The vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption) and CWE-770 (Allocation of Resources Without Limits or Throttling), indicating that the application fails to properly limit resource allocation, allowing malicious actors to exhaust system resources.
Critical Impact
Authenticated attackers can cause service disruption through resource exhaustion, potentially affecting file synchronization services across the entire QNAP NAS ecosystem.
Affected Products
- QNAP Qsync Central versions prior to 5.0.0.4
- QNAP NAS devices running vulnerable Qsync Central installations
Discovery Timeline
- 2026-01-20 - QNAP releases security patch in Qsync Central version 5.0.0.4
- 2026-02-11 - CVE-2025-54149 published to NVD
- 2026-02-12 - Last updated in NVD database
Technical Details for CVE-2025-54149
Vulnerability Analysis
This uncontrolled resource consumption vulnerability exists in QNAP Qsync Central's resource management mechanisms. The application does not properly enforce limits on resource allocation when processing certain operations, allowing an authenticated user to trigger excessive consumption of system resources such as CPU, memory, or disk I/O.
The attack requires local access with a valid user account, which limits the exposure compared to unauthenticated remote attacks. However, in environments where multiple users have access to the NAS system, this vulnerability presents a significant risk for internal denial-of-service attacks.
Root Cause
The root cause stems from insufficient bounds checking and resource limitation controls within Qsync Central. The application fails to implement proper throttling mechanisms or resource quotas when handling user-initiated operations. This allows authenticated users to submit requests or operations that consume disproportionate system resources without adequate safeguards in place to prevent abuse.
The dual classification under CWE-400 and CWE-770 indicates that the vulnerability involves both uncontrolled resource consumption patterns and inadequate resource allocation limits, suggesting a systemic issue in the application's resource management architecture.
Attack Vector
The attack is network-accessible but requires prior authentication with valid user credentials. An attacker who has compromised or legitimately obtained a user account on the QNAP NAS can exploit this vulnerability to exhaust system resources, resulting in degraded performance or complete service unavailability for all users of the Qsync Central service.
The exploitation does not require user interaction beyond the attacker's own actions, and the impact is limited to availability—no confidentiality or integrity breach has been identified with this vulnerability.
Detection Methods for CVE-2025-54149
Indicators of Compromise
- Abnormal resource consumption patterns (CPU, memory, disk I/O) associated with Qsync Central processes
- Unexpected service degradation or unavailability of file synchronization services
- Unusual user activity patterns showing repeated resource-intensive operations
- System logs indicating resource exhaustion or throttling events
Detection Strategies
- Monitor system resource utilization metrics for Qsync Central services and establish baseline thresholds
- Implement alerting for abnormal spikes in CPU, memory, or I/O usage attributed to qsync processes
- Review authentication logs for suspicious user account activity preceding resource exhaustion events
- Deploy endpoint detection solutions capable of identifying denial-of-service attack patterns
Monitoring Recommendations
- Configure SNMP or built-in QNAP monitoring to track resource consumption trends over time
- Set up automated alerts for when Qsync Central resource usage exceeds normal operational parameters
- Enable detailed audit logging for user operations within Qsync Central to support forensic analysis
- Consider implementing resource quotas at the operating system level as an additional safeguard
How to Mitigate CVE-2025-54149
Immediate Actions Required
- Update QNAP Qsync Central to version 5.0.0.4 or later immediately
- Review user accounts with access to Qsync Central and remove unnecessary privileges
- Implement monitoring for abnormal resource consumption as an interim detection measure
- Consider temporarily restricting Qsync Central access to trusted users only until patching is complete
Patch Information
QNAP has addressed this vulnerability in Qsync Central version 5.0.0.4, released on January 20, 2026. Organizations should update to this version or later to remediate the vulnerability. The security advisory is available at the QNAP Security Advisory QSA-26-02.
To update Qsync Central:
- Log in to the QNAP QTS or QuTS hero web interface
- Navigate to App Center
- Locate Qsync Central and check for available updates
- Install version 5.0.0.4 or later
Workarounds
- Restrict network access to the QNAP NAS to trusted networks and IP addresses only
- Implement strong authentication controls and review user account privileges regularly
- Configure resource limits at the operating system level where possible to contain potential abuse
- Monitor and audit user activities within Qsync Central for suspicious behavior patterns
# Verify Qsync Central version on QNAP NAS
# Access via SSH or the App Center in QTS web interface
# Ensure version is 5.0.0.4 or later
# Review installed applications
getcfg "Qsync Central" version -f /etc/config/qpkg.conf
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
