High severity · published Jan 2, 2026
CVE-2025-52863
A buffer overflow vulnerability has been reported to affect several QNAP operating system versions
8.1
CVSS
0.4%
EPSS
No
On KEV
Description
A buffer overflow vulnerability has been reported to affect several QNAP operating system versions. If a remote attacker gains a user account, they can then exploit the vulnerability to modify memory or crash processes.
We have already fixed the vulnerability in the following versions:
QTS 5.2.7.3256 build 20250913 and later
QuTS hero h5.2.7.3256 build 20250913 and later
QuTS hero h5.3.0.3192 build 20250716 and later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 29% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
QT
Qts · Qnap
5.2.0.2737; 5.2.0.2744; 5.2.0.2782; 5.2.0.2802; 5.2.0.2823; 5.2.0.2851; +10 more · source: NVD
QH
Quts Hero · Qnap
h5.2.0.2737; h5.2.0.2782; h5.2.0.2789; h5.2.0.2802; h5.2.0.2823; h5.2.0.2851; +12 more · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-52863
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-52863
Vendor Advisory
https://www.qnap.com/en/security-advisory/qsa-25-50
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