Medium severity · published Oct 3, 2025
CVE-2025-53406
QTS, QuTS hero
6.5
CVSS
0.4%
EPSS
No
On KEV
Description
A use of externally-controlled format string 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 obtain secret data or modify memory.
We have already fixed the vulnerability in the following versions:
QTS 5.2.6.3195 build 20250715 and later
QuTS hero h5.2.6.3195 build 20250715 and later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% 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.x before 5.2.6.3195 build 20250715 · source: vendor, NVD
QH
QuTS hero · QNAP Systems Inc.
h5.2.x before h5.2.6.3195 build 20250715 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-53406
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-53406
Vendor Advisory
https://www.qnap.com/en/security-advisory/qsa-25-36
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QuTS hero is not affected