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QtsApplication · Qnap

CVE-2021-44053

MEDIUM · 6.1 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 →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 cross-site scripting (XSS) vulnerability has been reported to affect QNAP device running QTS, QuTS hero and QuTScloud. If exploited, this vulnerability allows remote attackers to inject malicious code. We have already fixed this vulnerability in the following versions of QTS, QuTS hero and QuTScloud: QTS 4.5.4.1991 build 20220329 and later QTS 5.0.0.1986 build 20220324 and later QuTS hero h5.0.0.1986 build 20220324 and later QuTS hero h4.5.4.1971 build 20220310 and later QuTScloud c5.0.1.1949 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 stored cross-site scripting (XSS) vulnerability affecting QNAP NAS devices running QTS, QuTS hero, and QuTScloud firmware. Remote attackers can inject malicious JavaScript or HTML code through vulnerable input fields, which then executes in the browsers of other users viewing the affected content. The vulnerability is exploitable over the network without authentication and has medium severity due to the potential for session hijacking or credential theft.

MitigationApply the vendor-supplied firmware updates: QTS 4.5.4.1991 (build 20220329) or later, QTS 5.0.0.1986 (build 20220324) or later, QuTS hero h5.0.0.1986 (build 20220324) or later, QuTS hero h4.5.4.1971 (build 20220310) or later, or QuTScloud c5.0.1.1949 or later.

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
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 QNAP firmware type and version
    Log into the QNAP device via SSH or access the admin web interface. In QTS, go to Control Panel > System > Firmware > About. From command line, run `getcfg System.Version` or `cat /proc/uboot_version`. For QuTS hero or QuTScloud, the version string will include 'h' or 'c' prefix respectively.
    Affected if The firmware version cannot be determined or the device is not a QNAP NAS running QTS, QuTS hero, or QuTScloud.
  2. Confirm firmware is QTS and check version range
    If the version string starts with a number (e.g., 5.0.0.1716), this is QTS firmware. Compare your exact version number against these affected ranges: 5.0.0.1716 to 5.0.0.1985; 4.3.3.0174 to 4.3.3.1944; 4.3.4.0899 to 4.3.4.1975; 4.3.6.0895 to 4.3.6.1964; 4.4.0.0883 to 4.5.4.1990; or exactly version 4.2.6.
    Affected if Your QTS firmware version falls within any of these ranges or equals 4.2.6.
  3. Confirm firmware is QuTS hero and check version range
    If the version string starts with 'h' (e.g., h5.0.0.1772), this is QuTS hero firmware. Compare your version against: any version below h4.5.4.1771; or versions h5.0.0.1772 through h5.0.0.1985.
    Affected if Your QuTS hero firmware version is below h4.5.4.1771, or falls between h5.0.0.1772 and h5.0.0.1985 inclusive.
  4. Confirm firmware is QuTScloud and check version range
    If the version string starts with 'c' (e.g., c5.0.1.1948), this is QuTScloud firmware. Compare your version against versions below c5.0.1.1998.
    Affected if Your QuTScloud firmware version is below c5.0.1.1998.
  5. Verify network accessibility of the QNAP interface
    From an external network location, attempt to reach the QNAP admin web interface on ports 443 or 8080. Run `nmap -p 443,8080 <QNAP_IP>` or try accessing https://<QNAP_IP> in a browser.
    Affected if The QNAP admin interface is exposed to the network and the firmware version is in any affected range listed above.

If the device is a QNAP NAS running QTS, QuTS hero, or QuTScloud and the firmware version falls within the affected ranges specified for that firmware type, the device is vulnerable to CVE-2021-44053 and should be updated.

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

Apply the vendor-supplied firmware updates: QTS 4.5.4.1991 (build 20220329) or later, QTS 5.0.0.1986 (build 20220324) or later, QuTS hero h5.0.0.1986 (build 20220324) or later, QuTS hero h4.5.4.1971 (build 20220310) or later, or QuTScloud c5.0.1.1949 or later.

Recommended fix High confidence

QTS: 4.5.4.1991 (build 20220329) or 5.0.0.1986 (build 20220324); QuTS hero: h4.5.4.1971 or h5.0.0.1986; QuTScloud: c5.0.1.1949

  1. 1. Identify which QNAP product line is running: QTS, QuTS hero, or QuTScloud
  2. 2. For QTS 4.3.x versions: upgrade to QTS 4.5.4.1991 (build 20220329) or later
  3. 3. For QTS 5.0.0.x versions: upgrade to QTS 5.0.0.1986 (build 20220324) or later
  4. 4. For QuTS hero h4.5.x versions: upgrade to h4.5.4.1971 (build 20220310) or later
  5. 5. For QuTS hero h5.0.0.x versions: upgrade to h5.0.0.1986 (build 20220324) or later
  6. 6. For QuTScloud: upgrade to c5.0.1.1949 or later (or c5.0.1.1998 for full protection)
  7. 7. After upgrade, verify the QNAP firmware version matches or exceeds the fixed build numbers
Caveat Review QNAP release notes for any known compatibility issues before upgrading firmware

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-2021-44053 in production — separate from our analysis above.

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