Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from Vendor (qnap) · only source for this CVE.
CVSS VectorVendor: qnap
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
3DescriptionCVE.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: QuTS hero h5.2.9.3410 build 20260214 and later QuTS hero h5.3.4.3500 build 20260520 and later QuTS hero h6.0.0.3459 build 20260409 and later
AnalysisAI
NULL pointer dereference in QNAP QuTS hero NAS operating system allows a remote attacker who has already obtained or possesses an administrator account to trigger a denial-of-service condition, crashing affected services. Affected branches span QuTS hero h5.2.x, h5.3.x, and h6.0.x series, with vendor-released patches available as of early-to-mid 2026. No public exploit code or CISA KEV listing has been identified at time of analysis, and the mandatory prerequisite of high-privilege authentication substantially constrains real-world impact.
Technical ContextAI
QNAP QuTS hero is a ZFS-based NAS operating system developed by QNAP Systems Inc., differentiated from the standard QTS line by its use of the ZFS file system for data integrity and snapshot capabilities. The affected CPE is cpe:2.3:a:qnap_systems_inc.:quts_hero:*:*:*:*:*:*:*:* across multiple version branches. The root cause is classified as CWE-476 (NULL Pointer Dereference), a memory-safety weakness where code attempts to dereference a pointer that has not been initialized or has been set to NULL, causing the process to crash. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:H/UI:N) confirms the vulnerability is reachable over the network with low attack complexity and no special attack conditions, but strictly requires high-privilege (administrator-level) access. The sole impact is a low-severity availability degradation (VA:L), with no confidentiality or integrity consequences.
RemediationAI
The primary remediation is to upgrade QuTS hero to the patched versions released by QNAP: for the h5.2.x branch, upgrade to h5.2.9.3410 build 20260214 or later; for the h5.3.x branch, upgrade to h5.3.4.3500 build 20260520 or later; for the h6.0.x branch, upgrade to h6.0.0.3459 build 20260409 or later. Updates can be applied via the QNAP App Center or by downloading firmware directly from the QNAP support portal, referencing advisory QSA-26-38 at https://www.qnap.com/en/security-advisory/qsa-26-38. As a compensating control where immediate patching is not feasible, restrict administrator account access by enforcing strong unique passwords, enabling multi-factor authentication on the admin interface, and blocking external network access to the NAS management interface (typically port 8080/8443) at the perimeter firewall - this raises the bar for an attacker to first acquire the administrator credentials required to trigger the vulnerability. Note that blocking management ports may affect remote administration workflows.
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Same weakness CWE-476 – NULL Pointer Dereference
View allSame technique Denial Of Service
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External POC / Exploit Code
Leaving vuln.today
EUVD-2025-210097
GHSA-53hc-rhp5-vgx7