Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 2 May 2022.
QtsOperating system · Qnap

CVE-2020-2509

CRITICAL · 9.8 CVSS v3.1 Published 2021-04-17
Fix available
A fix is available. Upgrade to 4.2.6 / 4.3.6 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild 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 command injection vulnerability has been reported to affect QTS and QuTS hero. If exploited, this vulnerability allows attackers to execute arbitrary commands in a compromised application. We have already fixed this vulnerability in the following versions: QTS 4.5.2.1566 Build 20210202 and later QTS 4.5.1.1495 Build 20201123 and later QTS 4.3.6.1620 Build 20210322 and later QTS 4.3.4.1632 Build 20210324 and later QTS 4.3.3.1624 Build 20210416 and later QTS 4.2.6 Build 20210327 and later QuTS hero h4.5.1.1491 build 20201119 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 · moderate confidence

A command injection vulnerability in QNAP QTS and QuTS hero allows attackers to execute arbitrary commands in the compromised application. This is a critical flaw that can lead to full system compromise.

MitigationUpdate QTS or QuTS hero to one of the fixed versions listed in the official description. Immediately restrict network exposure of affected NAS devices until patching is complete.

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>= 4.3.5, < 4.3.6>= 4.4.0, < 4.5.1= 4.2.6= 4.3.3.0174= 4.3.3.0868= 4.3.3.0998= 4.3.3.1051= 4.3.3.1098= 4.3.3.1161= 4.3.3.1252= 4.3.3.1315
Quts HeroOperating system
Affected:< h4.5.1= h4.5.1= h4.5.1.1472

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 if QNAP QTS or QuTS hero is installed
    Access the QNAP admin web interface or run 'versus' command on the NAS CLI to identify the firmware type and version
    Affected if The system is running QNAP QTS or QuTS hero firmware
  2. Check QTS version against affected ranges
    In QTS web interface, go to Control Panel > System > Firmware Update > Check Firmware Version, or run 'getsysinfo' command via CLI to retrieve the exact version number
    Affected if Version is < 4.2.6, OR >= 4.3.5 and < 4.3.6, OR >= 4.4.0 and < 4.5.1, OR matches any of these specific versions: 4.2.6, 4.3.3.0174, 4.3.3.0868, 4.3.3.0998, 4.3.3.1051, 4.3.3.1098, 4.3.3.1161, 4.3.3.1252, 4.3.3.1315
  3. Check QuTS hero version against affected ranges
    In QuTS hero web interface, go to Control Panel > System > Firmware Update > Check Firmware Version, or run 'getsysinfo' command via CLI to retrieve the exact version number
    Affected if Version is < h4.5.1, equals h4.5.1, or equals h4.5.1.1472
  4. Determine if web interface is accessible
    Verify that the QNAP admin web interface (port 8080 or 443) is exposed to network by checking router/firewall rules or running 'netstat -an | grep -E "(8080|443)"'
    Affected if The QTS/QuTS hero web management interface is reachable from untrusted networks without VPN
  5. Check for signs of command injection exploitation
    Review system logs in Log Center for unexpected commands, new administrative accounts, or suspicious processes. Check /etc/config/.udocker/ or similar directories for unauthorized scripts
    Affected if Unauthorized commands appear in logs, unknown accounts exist, or unexpected processes are running

The environment is affected if QNAP QTS or QuTS hero is running any version that falls within the specified vulnerable ranges AND the web interface is network-accessible.

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 4.2.6 / 4.3.6 / 4.5.1 or later
Fixed in 4.2.64.3.64.5.1
Interim mitigation

Update QTS or QuTS hero to one of the fixed versions listed in the official description. Immediately restrict network exposure of affected NAS devices until patching is complete.

Recommended fix High confidence

QTS: 4.5.2.1566 (Build 20210202) or later for 4.5.x; 4.5.1.1495 (Build 20201123) or later for 4.4.x/4.5.0; 4.3.6.1620 (Build 20210322) or later for 4.3.5/4.3.6; 4.3.4.1632 (Build 20210324) or later for 4.3.4; 4.3.3.1624 (Build 20210416) or later for 4.3.3; 4.2.6 (Build 20210327) or later for 4.2.x.

  1. 1. Identify the current QTS or QuTS hero version by accessing the QNAP admin console and navigating to Control Panel > System > Firmware Update
  2. 2. Determine which version branch the current installation is on (4.2.x, 4.3.3, 4.3.4, 4.3.5, 4.3.6, 4.4.x, or 4.5.x)
  3. 3. For QTS 4.2.x systems: Upgrade to QTS 4.2.6 Build 20210327 or later
  4. 4. For QTS 4.3.3 systems: Upgrade to QTS 4.3.3.1624 Build 20210416 or later
  5. 5. For QTS 4.3.4 systems: Upgrade to QTS 4.3.4.1632 Build 20210324 or later
  6. 6. For QTS 4.3.5 or 4.3.6 systems: Upgrade to QTS 4.3.6.1620 Build 20210322 or later
  7. 7. For QTS 4.4.x or 4.5.0 systems: Upgrade to QTS 4.5.1.1495 Build 20201123 or later
  8. 8. For QTS 4.5.1 systems: Upgrade to QTS 4.5.2.1566 Build 20210202 or later
Caveat Review QNAP release notes for your specific version upgrade path as some legacy applications or configurations may not be compatible with newer QTS/QuTS hero versions

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

Fix this in Qts Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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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-2020-2509 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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