CVE-2025-29882: QNAP QTS NULL Pointer Dereference DoS Flaw

CVE-2025-29882 Overview

CVE-2025-29882 is a NULL pointer dereference vulnerability [CWE-476] affecting multiple versions of QNAP QTS and QuTS hero operating systems. An authenticated remote attacker with a valid user account can trigger the flaw to cause a denial-of-service (DoS) condition on the affected NAS device. QNAP addressed the issue in QTS 5.2.5.3145 build 20250526 and QuTS hero h5.2.5.3138 build 20250519.

Critical Impact
A remote attacker holding a low-privilege user account can crash affected QNAP NAS services, disrupting storage availability for connected users and applications.

Affected Products

QNAP QTS versions prior to 5.2.5.3145 build 20250526
QNAP QuTS hero versions prior to h5.2.5.3138 build 20250519
QNAP NAS appliances running the impacted firmware builds listed in QNAP Security Advisory QSA-25-21

Discovery Timeline

2025-08-29 - CVE-2025-29882 published to NVD
2026-09-26 - Last updated in NVD database

Technical Details for CVE-2025-29882

Vulnerability Analysis

The flaw is a NULL pointer dereference [CWE-476] in the QNAP operating system. When a specific code path receives unexpected input from an authenticated session, it dereferences a pointer that has not been validated for a NULL value. The dereference triggers a process crash, degrading or halting the affected service.

Because the vulnerable code path is reachable over the network, any attacker with valid credentials can invoke it remotely. The advisory scope is limited to availability impact; QNAP does not report confidentiality or integrity consequences from this issue.

Root Cause

The root cause is missing NULL validation before pointer dereference in the affected QTS and QuTS hero component. Under attacker-controlled conditions, the pointer resolves to NULL and the subsequent access raises a fault that terminates the service.

Attack Vector

Exploitation requires network access to the NAS management interface and a valid user account on the device. No user interaction is required beyond sending the crafted request. The result is a denial-of-service condition, not code execution or data disclosure.

No public proof-of-concept, exploit module, or in-the-wild exploitation has been reported. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2025-29882

Indicators of Compromise

Unexpected termination or repeated restarts of QTS or QuTS hero services on affected NAS devices
Kernel or application crash entries in /var/log referencing NULL pointer or segmentation faults
Loss of access to shared folders, iSCSI targets, or web administration for connected clients

Detection Strategies

Compare running firmware build strings against the fixed versions QTS 5.2.5.3145 build 20250526 and QuTS hero h5.2.5.3138 build 20250519.
Alert on authenticated sessions immediately preceding service crashes or process restarts on the appliance.
Correlate repeated authentication events from a single user account with abnormal service availability events.

Monitoring Recommendations

Forward NAS system and audit logs to a centralized SIEM for correlation with authentication activity.
Monitor availability of critical NAS-hosted services and generate alerts when uptime drops below expected thresholds.
Track user account creation and privilege changes on QTS and QuTS hero to reduce the pool of accounts an attacker could abuse.

How to Mitigate CVE-2025-29882

Immediate Actions Required

Upgrade affected devices to QTS 5.2.5.3145 build 20250526 or later, or QuTS hero h5.2.5.3138 build 20250519 or later.
Audit local user accounts on the NAS and remove or disable inactive, shared, or unnecessary accounts.
Restrict management interface exposure so it is not reachable from untrusted networks or the public internet.

Patch Information

QNAP resolved CVE-2025-29882 in QTS 5.2.5.3145 build 20250526 and QuTS hero h5.2.5.3138 build 20250519. Full remediation details are available in the QNAP Security Advisory QSA-25-21. Apply updates through the QTS App Center or the Control Panel firmware update workflow.

Workarounds

Place the NAS management interface behind a VPN or firewall rule that restricts access to trusted administrator subnets.
Enforce strong, unique passwords and multi-factor authentication for all QTS and QuTS hero user accounts.
Reduce the number of accounts with network login rights until the firmware update can be applied.

bash

# Verify current QTS or QuTS hero build via SSH
getcfg -f /etc/config/uLinux.conf System Version
getcfg -f /etc/config/uLinux.conf "Build Number"

# Compare against fixed builds:
#   QTS       >= 5.2.5.3145 build 20250526
#   QuTS hero >= h5.2.5.3138 build 20250519