Medium severity · published Feb 11, 2026
CVE-2025-66274
QTS, QuTS hero
4.9
CVSS
0.4%
EPSS
No
On KEV
Description
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 5.2.9.3410 build 20260214 and later QuTS hero h5.2.9.3410 build 20260214 and later QuTS hero h5.3.2.3354 build 20251225 and later QuTS hero h6.0.0.3397 build 20260206 and later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
QT
QTS · QNAP Systems Inc.
5.2.0 before 5.2.9.3410 build 20260214 · source: vendor
QH
QuTS hero · QNAP Systems Inc.
h5.2.0 before h5.2.9.3410 build 20260214; h5.3.0 before h5.3.2.3354 build 20251225; ? before h6.0.0.3397 build 20260206 · source: vendor, NVD
Affected product
QT
QTS
QNAP Systems Inc.
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CVE-2025-66276
QuTS hero is not affected