# CVE-2025-66280: QNAP QTS and QuTS hero integer overflow in operating system

Source: https://junglewise.ai/threats/cve-2025-66280-qnap-qts-and-quts-hero-integer-overflow-in-operating-system  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-10. Updated: 2026-06-10  
License: CC BY 4.0 with a link back

CVE-2025-66280 · Severity: info · CVSS 5.1 · Published 2026-06-10

QNAP operating systems, used to manage Network Attached Storage (NAS) devices for data storage and backup, are affected by a security vulnerability. If an attacker manages to obtain administrator credentials, they can exploit this flaw to further compromise the system's security and stability. This could lead to unauthorized changes to system settings or disruptions in data availability.

Technologies: [QNAP Systems, Inc. QuTS hero](https://junglewise.ai/threats/technologies/quts-hero). Vendors: [QNAP Systems, Inc.](https://junglewise.ai/threats/vendors/qnap-systems-inc).

## Quick answers

**Is CVE-2025-66280 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-66280 being exploited in the wild.

**How severe is CVE-2025-66280?** Informational severity, with a CVSS score of 5.1, published 10 June 2026.

**Which products and versions are affected?** QNAP QTS 5.2.9.3410 build 20260214 and later; QNAP QuTS hero h5.2.9.3410 build 20260214 and later; QNAP QuTS hero h5.3.4.3500 build 20260520 and later; QNAP QuTS hero h6.0.0.3397 build 20260206 and later.

**Is there a fix for CVE-2025-66280?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2025-66280 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2025-66280?** Check whether you run QNAP Systems or Inc. QuTS hero. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This vulnerability involves an integer overflow or wraparound (CWE-190) and a stack-based buffer overflow (CWE-121) within several QNAP operating system versions. The flaw is reachable over the network but requires high privileges (administrator account). Successful exploitation allows an authenticated attacker to compromise system integrity and availability. QNAP has released patches for QTS and QuTS hero to address these issues.

## Affected products

- QNAP QTS 5.2.9.3410 build 20260214 and later
- QNAP QuTS hero h5.2.9.3410 build 20260214 and later
- QNAP QuTS hero h5.3.4.3500 build 20260520 and later
- QNAP QuTS hero h6.0.0.3397 build 20260206 and later

## Timeline

- 2026-06-10: disclosed
- 2026-06-10: advisory

## References

- [https://www.qnap.com/en/security-advisory/qsa-26-10](https://www.qnap.com/en/security-advisory/qsa-26-10)

## Related threats

- [QNAP QTS and QuTS hero command injection](https://junglewise.ai/threats/cve-2026-24719-qnap-qts-and-quts-hero-command-injection)
- [QNAP QTS and QuTS hero NULL pointer dereference](https://junglewise.ai/threats/cve-2025-66281-qnap-qts-and-quts-hero-null-pointer-dereference)
- [QNAP QTS and QuTS hero command injection](https://junglewise.ai/threats/cve-2025-66279-qnap-qts-and-quts-hero-command-injection)
- [QNAP QuTS hero NULL pointer dereference causing DoS](https://junglewise.ai/threats/cve-2025-62850-qnap-quts-hero-null-pointer-dereference-causing-dos)
- [QNAP QTS and QuTS hero buffer overflow](https://junglewise.ai/threats/cve-2025-62858-qnap-qts-and-quts-hero-buffer-overflow)