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CVE-2025-66274 QNAP Systems Inc. CVE debrief

CVE-2025-66274 is a NULL pointer dereference vulnerability affecting several QNAP operating system versions. A remote attacker with administrator privileges can exploit this vulnerability to launch a denial-of-service (DoS) attack. The vulnerability has been fixed in 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, 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
2026-02-11
Original CVE updated
2026-06-09
Advisory published
2026-02-11
Advisory updated
2026-06-09

Who should care

Administrators of QNAP operating systems, particularly those using versions prior to the fixed versions mentioned above.

Technical summary

The vulnerability is a NULL pointer dereference, which can be exploited by a remote attacker with administrator privileges to launch a DoS attack. The CVSS score for this vulnerability is 5.1, indicating a medium severity.

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 h5.3.2.3354 build 20251225 or later
  • Update to QuTS hero h6.0.0.3397 build 20260206 or later

Evidence notes

The vulnerability has been reported by QNAP and is tracked under CVE-2025-66274. The CVSS vector for this vulnerability is CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

Official resources

CVE-2025-66274 was published on 2026-02-11T13:15:58.243Z and modified on 2026-06-09T08:16:26.640Z.