Vulnerability in QNAP Qts

CVE-2025-53406

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

EPSS: 0.003 (26.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-53406?
CVE-2025-53406 is a medium-severity vulnerability in QNAP Qts, classified under Use of Externally-Controlled Format String. CVSS score: 6.5/10. Published 2025-10-03.
How severe is CVE-2025-53406?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2025-53406 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.