What’s Vulnerable › Vulnerabilities

CVE-2025-66280: QTS, QuTS hero

• Severity: high (CVSS 7.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-10 · updated 2026-07-23
• Weakness: CWE-121

Description

An integer overflow or wraparound 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 compromise the security of the system. We have already fixed the vulnerability in the following versions: 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 QuTS hero h6.0.0.3397 build 20260206 and later

Affected products

• QNAP QTS: from 5.2.0.2737 before 5.2.9.3410 — fixed in 5.2.9.3410
• QNAP Systems Inc. QuTS hero: from h5.2.0.2737 before h5.2.9.3410; from h5.3.0.3115 before h5.3.4.3500; from h6.0.0.3324 before h6.0.0.3397 — fixed in h5.2.9.3410, h5.3.4.3500, h6.0.0.3397

How to fix

Upgrade to a fixed version: QNAP QTS 5.2.9.3410; QNAP Systems Inc. QuTS hero h5.2.9.3410, h5.3.4.3500, h6.0.0.3397. Check the vendor advisory for mitigations.

References

• https://www.qnap.com/en/security-advisory/qsa-26-10

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