CVE-2025-66276: QuTS hero is not affected. We have already fixed the vulnerability in the following version: QTS 5.2.7.3256 b

Q: How do I fix CVE-2025-66276?

qts: upgrade to 5.2.7.3256. Exact commands for each OS are on this page.

Q: Is CVE-2025-66276 being exploited?

CVE-2025-66276 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-66276 affect?

CVE-2025-66276 affects qts. Severity is critical (CVSS 9.8). QuTS hero is not affected. We have already fixed the vulnerability in the following version: QTS 5.2.7.3256 build 20250913 and later

Q: How urgent is CVE-2025-66276?

Priority 45/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2025-66276 is a critical-severity flaw (CVSS 9.8) affecting qts. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Published	2026-06-10
Last modified	2026-07-23

Publisher (CNA): QNAP Systems, Inc. · Vendor: qnap

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-10 03:16 UTCPublished CVE record published
2026-07-23 09:10 UTCUpdated Record last modified

qnap qts UPGRADE

Affected: >= 4.3.0 and < 5.2.7.3256

Fixed in: 5.2.7.3256

Safe to downgrade to: a release before 4.3.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-66276?

qts: upgrade to 5.2.7.3256. Exact commands for each OS are on this page.

Is CVE-2025-66276 being exploited?

CVE-2025-66276 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-66276 affect?

CVE-2025-66276 affects qts. Severity is critical (CVSS 9.8). 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 urgent is CVE-2025-66276?

Priority 45/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

QNAP vulnerabilities

Related CVEs

CVE-2025-66273 HIGH 7.2 UPGRADE UPGRADE A command injection vulnerability has been reported to affect several QNAP operating system versions
CVE-2025-66279 HIGH 7.2 UPGRADE UPGRADE A command injection vulnerability has been reported to affect several QNAP operating system versions
CVE-2026-22893 HIGH 7.2 UPGRADE UPGRADE A command injection vulnerability has been reported to affect several QNAP operating system versions
CVE-2026-24719 HIGH 7.2 UPGRADE UPGRADE A command injection vulnerability has been reported to affect several QNAP operating system versions
CVE-2025-66280 HIGH 7.2 UPGRADE UPGRADE An integer overflow or wraparound vulnerability has been reported to affect several QNAP operating system vers

References

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