How severe is CVE-2025-66274?

CVE-2025-66274 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-66274 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66274?

CVE-2025-66274 primarily affects Qnap Quts Hero. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-66274?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-66274 have an EU (EUVD) identifier?

Yes. CVE-2025-66274 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206925.

When was CVE-2025-66274 published?

CVE-2025-66274 was published on 2026-02-11 and last updated on 2026-06-17.

CVE-2025-66274

CVE-2025-66274 is a medium-severity vulnerability in Qnap Quts Hero with a CVSS 3.x base score of 4.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: Medium (CVSS 3.x base score 4.9)
CVSS v4: 5.1
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-206925
Weakness: CWE-476
Affected product: Qnap Quts Hero
Published: 2026-02-11
Last modified: 2026-06-17

Description

A NULL pointer dereference 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 launch a denial-of-service (DoS) attack. 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 h5.3.2.3354 build 20251225 and later QuTS hero h6.0.0.3397 build 20260206 and later

Frequently asked questions

What is CVE-2025-66274?: A NULL pointer dereference 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 launch a denial-of-service (DoS) attack. 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 h5.3.2.3354 build 20251225 and later QuTS hero h6.0.0.3397 build 20260206 and later
How severe is CVE-2025-66274?: CVE-2025-66274 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-66274 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66274?: CVE-2025-66274 primarily affects Qnap Quts Hero. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-66274?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-66274 have an EU (EUVD) identifier?: Yes. CVE-2025-66274 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206925.
When was CVE-2025-66274 published?: CVE-2025-66274 was published on 2026-02-11 and last updated on 2026-06-17.

References

https://www.qnap.com/en/security-advisory/qsa-26-08

Affected products (5)

cpe:2.3:o:qnap:quts_hero:h5.3.0.3115:build_20250430:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.3.0.3145:build_20250530:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.3.0.3192:build_20250716:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.3.1.3250:build_20250912:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.3.1.3292:build_20251024:*:*:*:*:*:*

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