Vulnary
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Critical· 9.2official fix available

CVE-2025-66276

A critical security flaw has been found in QNAP QTS firmware. The issue has been fixed in QTS 5.2.7.3256 build 20250913 and later. Users should update to the latest firmware to protect their devices.

publishedJun 10, 2026
last modifiedJul 23, 2026
sourcesNVD
severity · cvss
9.2
critical · how bad it is
exploitation · epss
<1%
21th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 22, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

QNAP QTS firmware on QNAP NAS devices, especially those running versions before 5.2.7.3256 build 20250913.

02

Real-world impact

If the flaw is exploited, an attacker could potentially compromise the confidentiality, integrity, or availability of the QNAP device.

03

Why this severity

The CVSS score of 9.2 reflects that the flaw can be exploited over the network without authentication and can have a high impact on confidentiality, integrity, and availability.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade QTS to version 5.2.7.3256 build 20250913 or later.

NVD-referenced vendor advisory

05

Timeline

  1. Jun 10, 2026 · Jun 10, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 23, 2026 · 12d ago
    Advisory updated
    The NVD record was last revised.
  3. Jul 23, 2026 · 12d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Attack requirementsPresent
Privileges requiredNone
User interactionNone needed
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →