How severe is CVE-2025-66276?

CVE-2025-66276 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-66276 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66276?

CVE-2025-66276 affects Qnap Qts. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-66276?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-66276 have an EU (EUVD) identifier?

Yes. CVE-2025-66276 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-210094.

When was CVE-2025-66276 published?

CVE-2025-66276 was published on 2026-06-10 and last updated on 2026-06-17.

CVE-2025-66276

CVE-2025-66276 is a critical-severity vulnerability in Qnap Qts with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.2
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-210094
Affected product: Qnap Qts
Published: 2026-06-10
Last modified: 2026-06-17

Description

QuTS hero is not affected. We have already fixed the vulnerability in the following version: QTS 5.2.7.3256 build 20250913 and later

Frequently asked questions

What is CVE-2025-66276?: QuTS hero is not affected. We have already fixed the vulnerability in the following version: QTS 5.2.7.3256 build 20250913 and later
How severe is CVE-2025-66276?: CVE-2025-66276 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-66276 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66276?: CVE-2025-66276 affects Qnap Qts. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-66276?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-66276 have an EU (EUVD) identifier?: Yes. CVE-2025-66276 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-210094.
When was CVE-2025-66276 published?: CVE-2025-66276 was published on 2026-06-10 and last updated on 2026-06-17.

References

https://www.qnap.com/en/security-advisory/qsa-25-56

Affected products (1)

cpe:2.3:o:qnap:qts:*:*:*:*:*:*:*:*

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