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QtsOperating system · Qnap

CVE-2021-38693

MEDIUM · 5.3 CVSS v3.1 Published 2022-05-05
Fix available
A fix is available. Upgrade to 4.5.4.1991 / 5.0.0.1986 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges 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 path traversal vulnerability has been reported to affect QNAP device running QuTScloud, QuTS hero, QTS, QVR Pro Appliance. If exploited, this vulnerability allows attackers to read the contents of unexpected files and expose sensitive data. We have already fixed this vulnerability in the following versions of QuTScloud, QuTS hero, QTS, QVR Pro Appliance: QuTScloud c5.0.1.1949 and later QuTS hero h5.0.0.1949 build 20220215 and later QuTS hero h4.5.4.1951 build 20220218 and later QTS 5.0.0.1986 build 20220324 and later QTS 4.5.4.1991 build 20220329 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 · high confidence

A path traversal vulnerability in QNAP devices running QuTScloud, QuTS hero, QTS, and QVR Pro Appliance allows remote attackers to read arbitrary files on the system by manipulating file path inputs, potentially exposing sensitive data.

MitigationUpgrade to the fixed versions: QuTScloud c5.0.1.1949+, QuTS hero h5.0.0.1949+/h4.5.4.1951+, QTS 5.0.0.1986+/4.5.4.1991+ or later releases.

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:< 4.5.4.1991>= 5.0.0.1716, < 5.0.0.1986
Quts HeroOperating system
Affected:>= h5.0.0.1772, < h5.0.0.1949
QutscloudOperating system
Affected:< c5.0.1.1949

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
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

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

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. Check QTS firmware version
    Log into QTS admin web interface, go to Control Panel > System > Firmware Update, or use 'grep -i version /etc/config/def_boot/bootpara' via SSH
    Affected if Version is < 4.5.4.1991 OR (>= 5.0.0.1716 AND < 5.0.0.1986)
  2. Check QuTS hero firmware version
    Log into QuTS hero admin web interface, navigate to Control Panel > System > Firmware Update, or check via SSH with 'getconf NASCORE_VER'
    Affected if Version is >= h5.0.0.1772 AND < h5.0.0.1949
  3. Check QuTScloud firmware version
    Access QuTScloud via admin web interface or run 'cat /etc/osrelease' via SSH to view the version string
    Affected if Version is < c5.0.1.1949
  4. Verify web file service is enabled
    Check if the file manager or web-based file browsing service is active in Control Panel > Applications > QTS Service Manager
    Affected if The web-based file path input feature is exposed to network (likely default)

A device is affected if it runs any of the QNAP firmware variants (QTS, QuTS hero, QuTScloud) within the version ranges listed and has network-accessible file handling interfaces.

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
Upgrade available Upgrade to 4.5.4.1991 / 5.0.0.1986 or later
Fixed in 4.5.4.19915.0.0.1986
Interim mitigation

Upgrade to the fixed versions: QuTScloud c5.0.1.1949+, QuTS hero h5.0.0.1949+/h4.5.4.1951+, QTS 5.0.0.1986+/4.5.4.1991+ or later releases.

Recommended fix High confidence

Minimum fixed versions: QTS 4.5.4.1991, QTS 5.0.0.1986, QuTS hero h5.0.0.1949, QuTS hero h4.5.4.1951, QuTScloud c5.0.1.1949

  1. Identify which QNAP system is in use (QTS, QuTS hero, or QuTScloud)
  2. Check the current version of the system to confirm it is within an affected version range
  3. For QTS 4.5.x: Update to version 4.5.4.1991 (build 20220329) or later
  4. For QTS 5.0.x: Update to version 5.0.0.1986 (build 20220324) or later
  5. For QuTS hero h5.0.x: Update to version h5.0.0.1949 (build 20220215) or later
  6. For QuTS hero h4.5.x: Update to version h4.5.4.1951 (build 20220218) or later
  7. For QuTScloud: Update to version c5.0.1.1949 or later
  8. After update, verify the system is running a fixed version

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

Fix this in Qts Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,090
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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-2021-38693 in production — separate from our analysis above.

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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