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QtsOperating system · Qnap

CVE-2025-48721

MEDIUM · 6.5 CVSS v3.1 Published 2026-01-02
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A buffer overflow 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 modify memory or crash processes. We have already fixed the vulnerability in the following version: QTS 5.2.8.3332 build 20251128 and later

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A buffer overflow vulnerability in QNAP QTS operating system allows an authenticated remote attacker with administrator privileges to modify memory or crash processes. The vulnerability requires prior compromise of an administrator account before exploitation.

MitigationUpdate QNAP QTS to version 5.2.8.3332 build 20251128 or later. Until then, enforce strict access controls on administrator accounts and monitor for unauthorized admin access.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
QtsOperating system
Affected:= 5.2.0.2737= 5.2.0.2744= 5.2.0.2782= 5.2.0.2802= 5.2.0.2823= 5.2.0.2851= 5.2.0.2860= 5.2.1.2930= 5.2.2.2950= 5.2.3.3006= 5.2.4.3070= 5.2.4.3079
Quts HeroOperating system
Affected:= h5.2.0.2737= h5.2.0.2782= h5.2.0.2789= h5.2.0.2802= h5.2.0.2823= h5.2.0.2851= h5.2.0.2860= h5.2.1.2929= h5.2.1.2940= h5.2.2.2952= h5.2.3.3006= h5.2.4.3070

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify QNAP product type
    Log into the QNAP device admin interface or check system information to determine if the operating system is QTS or QuTS Hero
    Affected if Product is QTS or QuTS Hero and matches affected versions in step 2
  2. Check QTS firmware version
    Navigate to Control Panel > System > Firmware Update or use the command line to query the firmware version (e.g., cat /etc/version)
    Affected if Version equals any of: 5.2.0.2737, 5.2.0.2744, 5.2.0.2782, 5.2.0.2802, 5.2.0.2823, 5.2.0.2851, 5.2.0.2860, 5.2.1.2930, 5.2.2.2950, 5.2.3.3006, 5.2.4.3070, or 5.2.4.3079
  3. Check QuTS Hero firmware version
    Navigate to Control Panel > System > Firmware Update or use the command line to query the firmware version
    Affected if Version equals any of: h5.2.0.2737, h5.2.0.2782, h5.2.0.2789, h5.2.0.2802, h5.2.0.2823, h5.2.0.2851, h5.2.0.2860, h5.2.1.2929, h5.2.1.2940, h5.2.2.2952, h5.2.3.3006, or h5.2.4.3070
  4. Review administrator account activity
    Check admin audit logs and user access records for any unauthorized or unexpected administrator logins, especially from unusual IP addresses or at unusual times
    Affected if Administrator accounts have been compromised or accessed by unauthorized parties

The environment is affected if the device runs QTS or QuTS Hero with a version matching one of the exact versions listed AND an attacker has obtained administrator credentials.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update QNAP QTS to version 5.2.8.3332 build 20251128 or later. Until then, enforce strict access controls on administrator accounts and monitor for unauthorized admin access.

Recommended fix High confidence

QTS 5.2.8.3332 build 20251128 or later

  1. 1. Log into the QNAP admin interface
  2. 2. Navigate to Control Panel > System > Firmware Update
  3. 3. Check the current QTS or QTS Hero version under System Information to confirm if affected
  4. 4. Use the firmware update function to upgrade to QTS 5.2.8.3332 (build 20251128) or later
  5. 5. Verify the upgrade completed successfully and the new version is running
Caveat Firmware upgrades carry inherent risk; ensure backups are in place and follow QNAP upgrade best practices before proceeding

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Qts Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-48721 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data