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PatchSiren cyber security CVE debrief

CVE-2025-66280 QNAP Systems Inc. CVE debrief

CVE-2025-66280 is a medium-severity vulnerability (CVSS score: 5.1) affecting several QNAP operating system versions. The vulnerability is caused by an integer overflow or wraparound weakness, which can be exploited by a remote attacker with administrator privileges to compromise the security of the system. QNAP has released patched versions to address this issue: QTS 5.2.9.3410 build 20260214 and later, QuTS hero h5.2.9.3410 build 20260214 and later, QuTS hero h5.3.4.3500 build 20260520 and later, and QuTS hero h6.0.0.3397 build 20260206 and later.

Vendor
QNAP Systems Inc.
Product
QTS
CVSS
MEDIUM 5.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-10
Original CVE updated
2026-06-15
Advisory published
2026-06-10
Advisory updated
2026-06-15

Who should care

Administrators and users of QNAP operating systems, particularly those using versions prior to the patched releases, should be aware of this vulnerability and take necessary actions to update their systems.

Technical summary

The vulnerability is caused by an integer overflow or wraparound weakness (CWE-121, CWE-190). A remote attacker with administrator privileges can exploit this vulnerability to compromise the security of the system.

Defensive priority

Medium

Recommended defensive actions

  • Update to QTS 5.2.9.3410 build 20260214 or later
  • Update to QuTS hero h5.2.9.3410 build 20260214 or later
  • Update to QuTS hero h5.3.4.3500 build 20260520 or later
  • Update to QuTS hero h6.0.0.3397 build 20260206 or later

Evidence notes

The CVE record and NVD detail can be found at [cve-org](https://www.cve.org/CVERecord?id=CVE-2025-66280) and [nvd](https://nvd.nist.gov/vuln/detail/CVE-2025-66280), respectively. Additional information is available at [ref-4](https://www.qnap.com/en/security-advisory/qsa-26-10).

Sources and references

Verified primary and authoritative sources

  • CVE-2025-66280 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-66280

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2025-66280 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-66280

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.