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QtsOperating system · Qnap

CVE-2018-0721

HIGH · 7.7 CVSS v3.1 Published 2018-11-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
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
Buffer Overflow vulnerability in NAS devices. QTS allows attackers to run arbitrary code. This issue affects: QNAP Systems Inc. QTS version 4.2.6 and prior versions on build 20180711; version 4.3.3 and prior versions on build 20180725; version 4.3.4 and prior versions on build 20180710.

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

Buffer overflow vulnerability in QNAP QTS operating system allows remote attackers to execute arbitrary code via crafted requests. Affected versions include QTS 4.2.6 and prior (build 20180711), 4.3.3 and prior (build 20180725), and 4.3.4 and prior (build 20180710).

MitigationUpdate QTS firmware to versions beyond the vulnerable builds (post-20180711 for 4.2.x, post-20180725 for 4.3.3, post-20180710 for 4.3.4) as specified in QNAP security advisories.

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:= 4.2.6= 4.3.3= 4.3.4

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
High
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
High
Availability
Low

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

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. Locate QTS version in admin interface
    Log into QNAP QTS web admin panel (usually http://[NAS-IP]:8080 or https://[NAS-IP]:8081). Navigate to Control Panel > System > System Settings > Firmware Version. Record the displayed QTS version and build number.
    Affected if Version shows 4.2.6 or lower, 4.3.3 or lower, or 4.3.4 or lower, OR build number is 20180711 or earlier for 4.2.x, 20180725 or earlier for 4.3.3, or 20180710 or earlier for 4.3.4
  2. Check QTS version via command line
    Access the NAS via SSH (using Putty or terminal). Run command: cat /etc/config/qts_version . This displays the exact QTS version and build date.
    Affected if Output shows any version matching the vulnerable ranges above
  3. Identify exposed network services
    From the QTS admin interface, check Control Panel > Network & File Services > Telnet/SSH. Determine if SSH or Telnet access is enabled and accessible from untrusted networks.
    Affected if Remote SSH/Telnet access is enabled and the device is internet-facing, increasing attack surface for remote exploitation
  4. Verify QNAP cloud connectivity status
    Check Control Panel > myQNAPcloud. Review whether the device is registered for cloud access and if port forwarding or UPnP is configured.
    Affected if myQNAPcloud service is active and exposes QTS interfaces externally, allowing remote attackers to reach the vulnerable component

The device is affected if running QTS version 4.2.6 or lower (build up to 20180711), 4.3.3 or lower (build up to 20180725), or 4.3.4 or lower (build up to 20180710), and has network exposure enabling remote attackers to send crafted requests.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update QTS firmware to versions beyond the vulnerable builds (post-20180711 for 4.2.x, post-20180725 for 4.3.3, post-20180710 for 4.3.4) as specified in QNAP security advisories.

Fix this in Qts Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2018-0721 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
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