CyberSecBulletin
CVE-2025-66281NVD status: Analyzed

QTS: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2025-66281 is a high-severity NULL pointer dereference vulnerability in QTS from QNAP, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists version 5.2.9.3410 build 20260214 as the first without the flaw, so updating QTS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.46% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update QTS to 5.2.9.3410 build 20260214 or a later version.
  2. Update QuTS hero to h5.2.9.3410 build 20260214 or h5.3.4.3500 build 20260520 or h6.0.0.3397 build 20260206, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
QNAPQTS5.2.0 up to, but not including, 5.2.9.3410 build 202602145.2.9.3410 build 20260214
QNAPQuTS heroh5.2.0 up to, but not including, h5.2.9.3410 build 20260214; h5.3.0 up to, but not including, h5.3.4.3500 build 20260520; ? up to, but not including, h6.0.0.3397 build 20260206h5.2.9.3410 build 20260214, h5.3.4.3500 build 20260520, h6.0.0.3397 build 20260206

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
HighAdministrator-level access is required first.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.06.9MediumCNA (qnapsecurity.com.tw)
CVSS 3.17.2HighNVD

Official description

A NULL pointer dereference vulnerability has been reported to affect several QNAP operating system versions. The remote attackers can then exploit the vulnerability to launch a denial-of-service (DoS) attack. We have already fixed the vulnerability in the following versions: QTS 5.2.9.3410 build 20260214 and later QuTS hero h5.2.9.3410 build 20260214 and later QuTS hero h5.3.4.3500 build 20260520 and later QuTS hero h6.0.0.3397 build 20260206 and later

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

Other vulnerabilities in QTS

All QTS vulnerabilities

Recent NULL Pointer Dereference vulnerabilities

Spotted an error? Tell us.