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Qvr EliteApplication · Qnap

CVE-2021-38691

CRITICAL · 9.8 CVSS v3.1 Published 2022-01-14
Fix available
A fix is available. Upgrade to 2.1.3.0 / 2.1.4.0 or later.
See remediation →
100/100
Remediation priority · Urgent
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 stack buffer overflow vulnerability has been reported to affect QNAP device running QVR Elite, QVR Pro, QVR Guard. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of QVR Elite, QVR Pro, QVR Guard: QuTS hero h5.0.0: QVR Elite 2.1.4.0 (2021/12/06) and later QuTS hero h4.5.4: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 5.0.0: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 4.5.4: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 4.5.4: QVR Pro 2.1.3.0 (2021/12/06) and later QTS 5.0.0: QVR Pro 2.1.3.0 (2021/12/06) and later QTS 4.5.4: QVR Guard 2.1.3.0 (2021/12/06) and later QTS 5.0.0: QVR Guard 2.1.3.0 (2021/12/06) 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 stack buffer overflow vulnerability in QNAP QVR Elite, QVR Pro, and QVR Guard allows remote attackers to execute arbitrary code due to insufficient bounds checking in the video surveillance software running on QNAP devices.

MitigationApply the vendor patches: upgrade QVR Elite to version 2.1.4.0 or later, or QVR Pro/QVR Guard to version 2.1.3.0 or later (released 2021/12/06), corresponding to the affected QuTS hero or QTS firmware versions.

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
Qvr EliteApplication
Affected:< 2.1.4.0
Qvr GuardApplication
Affected:< 2.1.3.0
Qvr ProApplication
Affected:< 2.1.3.0

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 installed QVR application
    Log into QNAP QTS/QuTS hero admin interface and navigate to App Center to view installed surveillance applications, or run 'ls /share/CACHEDEV1_DATA/.qpkg/QVR/' to list QVR components
    Affected if QVR Elite, QVR Pro, or QVR Guard is installed on the device
  2. Determine QVR Elite version
    In QTS/QuTS hero, go to App Center > QVR Elite > click the version number, or run command 'qpkg --get-versions QVR' to retrieve version info
    Affected if version is found to be below 2.1.4.0
  3. Determine QVR Pro version
    In QTS/QuTS hero, go to App Center > QVR Pro > click the version number, or run command 'qpkg --get-versions QVRPro' to retrieve version info
    Affected if version is found to be below 2.1.3.0
  4. Determine QVR Guard version
    In QTS/QuTS hero, go to App Center > QVR Guard > click the version number, or run command 'qpkg --get-versions QVRGuard' to retrieve version info
    Affected if version is found to be below 2.1.3.0

The device is affected if any of QVR Elite (version < 2.1.4.0), QVR Pro (version < 2.1.3.0), or QVR Guard (version < 2.1.3.0) is installed and the QVR service is exposed to the network.

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 2.1.3.0 / 2.1.4.0 or later
Fixed in 2.1.3.02.1.4.0
Interim mitigation

Apply the vendor patches: upgrade QVR Elite to version 2.1.4.0 or later, or QVR Pro/QVR Guard to version 2.1.3.0 or later (released 2021/12/06), corresponding to the affected QuTS hero or QTS firmware versions.

Recommended fix High confidence

QVR Elite 2.1.4.0 or later; QVR Pro 2.1.3.0 or later; QVR Guard 2.1.3.0 or later

  1. 1. Identify which QVR product is installed on the QNAP device (QVR Elite, QVR Pro, or QVR Guard)
  2. 2. Check the current version of the installed QVR software in the QNAP admin interface
  3. 3. For QVR Elite: Upgrade to version 2.1.4.0 or later (released 2021/12/06)
  4. 4. For QVR Pro: Upgrade to version 2.1.3.0 or later (released 2021/12/06)
  5. 5. For QVR Guard: Upgrade to version 2.1.3.0 or later (released 2021/12/06)
  6. 6. Download the appropriate update from the QNAP App Center or QNAP download center
  7. 7. Install the update following QNAP's standard upgrade procedure
  8. 8. Verify the installed version matches or exceeds the fixed version

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

Fix this in Qvr Elite 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-2021-38691 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