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QtsApplication · Qnap

CVE-2021-44052

HIGH · 8.1 CVSS v3.1 Published 2022-05-05
Fix available
A fix is available. Upgrade to 4.3.3.1945 / 4.3.4.1976 or later.
See remediation →
87/100
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
An improper link resolution before file access ('Link Following') vulnerability has been reported to affect QNAP device running QuTScloud, QuTS hero, and QTS. If exploited, this vulnerability allows remote attackers to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. We have already fixed this vulnerability in the following versions of QuTScloud, QuTS hero, and QTS: QuTScloud c5.0.1.1998 and later QuTS hero h4.5.4.1971 build 20220310 and later QuTS hero h5.0.0.1986 build 20220324 and later QTS 4.3.4.1976 build 20220303 and later QTS 4.3.3.1945 build 20220303 and later QTS 4.2.6 build 20220304 and later QTS 4.3.6.1965 build 20220302 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

This is a path traversal vulnerability via improper symlink resolution in QNAP NAS firmware. Attackers can exploit this to traverse the file system beyond intended boundaries and read or overwrite arbitrary files on the device.

MitigationUpdate the QNAP device firmware to one of the specified fixed versions (QuTScloud c5.0.1.1998+, QuTS hero h4.5.4.1971 build 20220310+, QTS 4.2.6 build 20220304+, or QTS 5.0.0.1986 build 20220324+).

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
QtsApplication
Affected:>= 5.0.0.1716, < 5.0.0.1986>= 4.3.3.0174, < 4.3.3.1945>= 4.3.4.0899, < 4.3.4.1976>= 4.3.6.0895, < 4.3.6.1965>= 4.4.0.0883, < 4.5.4.1991= 4.2.6
Quts HeroOperating system
Affected:< h4.5.4.1771>= h5.0.0.1772, < h5.0.0.1986
QutscloudOperating system
Affected:< c5.0.1.1998

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

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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. Identify the QNAP product model
    Access the QNAP device via SSH or web interface and run `getsysinfo` or check System Settings > System > Device Information to identify whether the device runs QuTS, QuTS Hero, or QuTScloud
    Affected if Device is any QNAP NAS model running QuTS, QuTS Hero, or QuTScloud firmware
  2. Determine installed firmware version
    In the web interface go to Control Panel > System > Device Information > Firmware Version, or via SSH run `fw_cli -v` or check `/etc/config/def_para` for the build number
    Affected if Firmware version cannot be determined or is below the fixed releases
  3. Compare QTS version against affected ranges
    If running QTS, compare the version to: 5.0.0.1716-5.0.0.1986, 4.3.3.0174-4.3.3.1945, 4.3.4.0899-4.3.4.1976, 4.3.6.0895-4.3.6.1965, 4.4.0.0883-5.0.0.1986, or 4.2.6
    Affected if Installed QTS version falls within any of the vulnerable ranges listed
  4. Compare QuTS Hero version against affected ranges
    If running QuTS Hero, compare the version to: h4.5.4.1771 and below, or h5.0.0.1772 to h5.0.0.1986
    Affected if Installed QuTS Hero version is h4.5.4.1771 or below, or between h5.0.0.1772 and h5.0.0.1985
  5. Compare QuTScloud version against affected ranges
    If running QuTScloud, check if the version is below c5.0.1.1998
    Affected if Installed QuTScloud version is c5.0.1.1997 or earlier

The device is affected if it runs any QNAP QuTS, QuTS Hero, or QuTScloud firmware version within the vulnerable ranges specified in the CVE, regardless of whether the management interface is exposed to the internet.

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 4.3.3.1945 / 4.3.4.1976 / 4.3.6.1965 or later
Fixed in 4.3.3.19454.3.4.19764.3.6.1965
Interim mitigation

Update the QNAP device firmware to one of the specified fixed versions (QuTScloud c5.0.1.1998+, QuTS hero h4.5.4.1971 build 20220310+, QTS 4.2.6 build 20220304+, or QTS 5.0.0.1986 build 20220324+).

Recommended fix High confidence

QTS: 5.0.0.1986+, 4.5.4.1991+, 4.3.6.1965+, 4.3.4.1976+, 4.3.3.1945+, 4.2.6+ | QuTS hero: h4.5.4.1971+, h5.0.0.1986+ | QuTScloud: c5.0.1.1998+

  1. 1. Identify the current QNAP QTS, QuTS hero, or QuTScloud version installed on the device
  2. 2. Determine which product line and version range applies to your system from the affected versions list
  3. 3. For QTS systems: upgrade to one of the fixed versions: QTS 5.0.0.1986 (build 20220324 or later), QTS 4.5.4.1991 (build 20220329 or later), QTS 4.3.6.1965 (build 20220302 or later), QTS 4.3.4.1976 (build 20220303 or later), QTS 4.3.3.1945 (build 20220303 or later), or QTS 4.2.6 (build 20220304 or later)
  4. 4. For QuTS hero systems: upgrade to h4.5.4.1971 (build 20220310 or later) or h5.0.0.1986 (build 20220324 or later)
  5. 5. For QuTScloud systems: upgrade to c5.0.1.1998 or later
  6. 6. Perform the upgrade via the QNAP App Center or firmware update utility following standard QNAP upgrade procedures
  7. 7. After upgrade, verify the system is running a fixed version and monitor for any issues
Caveat Standard QNAP firmware upgrade risks apply - ensure backups are current and review release notes for any known issues before proceeding

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
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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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-2021-44052 in production — separate from our analysis above.

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