Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain QNAP admin credentials via credential reuse or brute force
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DeliveryAuthenticate remotely to QNAP management interface
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ExploitSend crafted request to vulnerable OS component
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ExecutionTrigger CWE-476 NULL pointer dereference
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PersistCrash system process
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ImpactCause denial-of-service
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Null pointer safety, defensive checks
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires the attacker to hold a valid administrator account on the target QNAP device; this is confirmed by the CVSS 4.0 vector PR:H (High Privileges Required). An unauthenticated remote attacker cannot directly trigger this vulnerability. The limiting factor is this elevated authentication prerequisite - an attacker must first compromise admin credentials through a separate vector (credential reuse, brute force, phishing) before the NULL pointer dereference becomes reachable. No special non-default configuration or specific feature enablement is stated in available data beyond the admin account requirement. Affected devices running QTS or QuTS hero within the vulnerable version ranges are at risk once the admin access prerequisite is met. |
| Impact | The CVSS 4.0 base score of 5.1 (Medium) accurately reflects the constrained threat model: network reachable (AV:N) with low attack complexity (AC:L), but gated entirely behind high-privilege authentication (PR:H), which substantially limits the realistic attacker population to those who have already compromised an admin account. The impact is further bounded - confidentiality impact is Low (VC:L) and availability impact is Low (VA:L), with no integrity or scope change. No EPSS score was provided in the available data, precluding probabilistic exploitation likelihood comparison. This vulnerability is absent from the CISA KEV catalog and no public exploit code has been identified. The primary real-world risk vector is QNAP devices exposed to the internet with weak, reused, or previously breached administrator credentials - a known endemic problem for QNAP deployments. Organizations with properly hardened admin access and network-segmented NAS devices face low realistic risk. |
| Exploit ScenarioDerived | An attacker who has obtained administrator credentials to a QNAP NAS - through credential stuffing, phishing, or reuse of previously leaked passwords - authenticates remotely to the management interface and sends a specially crafted request that triggers a NULL pointer dereference within the OS, causing a targeted system crash or prolonged service interruption. No public exploit code exists at time of analysis, so exploitation currently requires manual knowledge of the vulnerable code path. |
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Alert meAnalysisAIv1 – Jun 10, 2026
NULL pointer dereference in QNAP QTS and QuTS hero NAS operating systems enables a remote, administrator-authenticated attacker to trigger a denial-of-service condition. Exploitation requires the attacker to first hold or acquire an administrator account on the target device, after which a crafted request can crash system services. No public exploit code has been identified and this vulnerability is not listed in the CISA KEV catalog at time of analysis.
RemediationAI
Upgrade to a fixed release as confirmed by QNAP advisory QSA-26-18 (https://www.qnap.com/en/security-advisory/qsa-26-18): QTS users should update to version 5.2.9.3492 build 20260507 or later; QuTS hero users should update to h5.2.9.3499 build 20260514, h5.3.4.3500 build 20260520, or h6.0.0.3459 build 20260409 depending on their branch. As a compensating control where immediate patching is not feasible, restrict administrator account access by enforcing multi-factor authentication on the QNAP management interface, disabling remote admin login from untrusted networks, and ensuring the admin panel is not exposed to the public internet - QNAP devices with admin interfaces on public IPs are a known high-risk posture. Note that these controls mitigate the precondition (admin credential compromise) rather than the vulnerability itself.
Affected VersionsENISA
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Technical ContextAI · show details
The vulnerability is a CWE-476 (NULL Pointer Dereference) in QNAP's proprietary NAS operating systems QTS and QuTS hero, as confirmed by CPE strings cpe:2.3:a:qnap_systems_inc.:qts and cpe:2.3:a:qnap_systems_inc.:quts_hero. NULL pointer dereferences arise when code attempts to read from or write to memory through a pointer that has not been initialized or was explicitly set to NULL, causing the process to fault and crash. In the QNAP context, this results in service disruption rather than code execution, consistent with the Low availability impact scored under CVSS 4.0. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:H/UI:N) indicates the flaw is reachable over the network with no additional tactics required, but mandates that the attacker already holds high-privilege (administrator-level) credentials on the device.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:U
Primary rating from Vendor (qnap) · only source for this CVE.
CVSS VectorVendor: qnap
Lifecycle Timeline
5DescriptionCVE.org
A NULL pointer dereference vulnerability has been reported to affect several QNAP operating system versions. If a remote attacker gains an administrator account, they can then exploit the vulnerability to launch a denial-of-service (DoS) attack.
We have already fixed the vulnerability in the following versions: QTS 5.2.9.3492 build 20260507 and later QuTS hero h5.2.9.3499 build 20260514 and later QuTS hero h5.3.4.3500 build 20260520 and later QuTS hero h6.0.0.3459 build 20260409 and later
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
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GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed function definitions in the values of
QNAP QTS before 4.2.4 Build 20170313 allows attackers to execute arbitrary commands via unspecified vectors. Rated criti
QNAP QTS before 4.2.4 Build 20170313 allows attackers to gain administrator privileges and obtain sensitive information
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QNAP QTS before 4.2.4 Build 20170313 allows attackers to gain administrator privileges and execute arbitrary commands vi
QNAP QTS before 4.2.4 Build 20170313 allows local users to obtain sensitive Domain Administrator password information by
This command injection vulnerability in QTS allows attackers to run arbitrary commands in the compromised application. R
This improper input validation vulnerability allows remote attackers to inject arbitrary code to the system. Rated criti
A prototype pollution vulnerability has been reported to affect several QNAP operating system versions. Rated high sever
A buffer overflow vulnerability in external device function in QNAP QTS version 4.2.6 build 20171026, 4.3.3.0378 build 2
A buffer overflow vulnerability in password function in QNAP QTS version 4.2.6 build 20171026, 4.3.3.0378 build 20171117
EUVD-2026-35975
GHSA-9vf8-xh83-h327
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB