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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 26 Mar 2024.
SurelineApplication · Sunhillo

CVE-2021-36380

CRITICAL · 9.8 CVSS v3.1 Published 2021-08-13
Fix available
A fix is available. Upgrade to 8.7.0.1.1 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit 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
Sunhillo SureLine before 8.7.0.1.1 allows Unauthenticated OS Command Injection via shell metacharacters in ipAddr or dnsAddr /cgi/networkDiag.cgi.

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

Sunhillo SureLine versions before 8.7.0.1.1 contain an unauthenticated OS command injection vulnerability in the /cgi/networkDiag.cgi endpoint. Attackers can inject arbitrary OS commands through the ipAddr or dnsAddr parameters using shell metacharacters, achieving remote code execution without any authentication.

MitigationUpgrade to version 8.7.0.1.1 or later which patches the command injection vulnerability; if immediate upgrade is not possible, disable networkDiag.cgi or restrict access to the CGI interface via network segmentation.

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
SurelineApplication
Affected:< 8.7.0.1.1

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 the Sunhillo SureLine installation
    Check for the presence of SureLine web interface or examine system documentation to confirm the product name and manufacturer.
    Affected if The system is not running Sunhillo SureLine, then this CVE does not apply.
  2. Determine the installed SureLine version
    Access the SureLine administrative interface or check system files to retrieve the current firmware/software version number.
    Affected if The installed version is less than 8.7.0.1.1, placing it within the affected range.
  3. Locate the networkDiag.cgi script
    Check if the file networkDiag.cgi exists in the web server's cgi-bin directory, typically under /cgi/ or /cgi-bin/ on the SureLine device.
    Affected if The script is present and accessible via HTTP/HTTPS.
  4. Verify CGI parameter exposure
    Attempt to access networkDiag.cgi with the ipAddr or dnsAddr parameters via HTTP GET or POST request to confirm the endpoint accepts these inputs.
    Affected if The script accepts ipAddr or dnsAddr parameters without requiring authentication.
  5. Confirm lack of input sanitization
    Send a test request with shell metacharacters (such as ; or |) in the ipAddr or dnsAddr parameter to observe if the application executes the injected command.
    Affected if The application returns command output or exhibits unexpected behavior indicating command execution occurred.

A system is affected if it runs Sunhillo SureLine version below 8.7.0.1.1 and has the networkDiag.cgi script accessible with the ipAddr or dnsAddr parameters exposed without authentication.

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 8.7.0.1.1 or later
Fixed in 8.7.0.1.1
Interim mitigation

Upgrade to version 8.7.0.1.1 or later which patches the command injection vulnerability; if immediate upgrade is not possible, disable networkDiag.cgi or restrict access to the CGI interface via network segmentation.

Recommended fix High confidence

8.7.0.1.1

  1. Download the latest SureLine firmware version 8.7.0.1.1 or later from the official Sunhillo support portal
  2. Access the SureLine administrative web interface
  3. Navigate to System Settings > Firmware Upgrade or similar upgrade section
  4. Upload the downloaded firmware file
  5. Confirm the upgrade and wait for the device to reboot
  6. Verify the upgrade was successful by checking the firmware version in the web interface
  7. Test that the /cgi/networkDiag.cgi endpoint is functioning properly after upgrade

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

Fix this in Sureline Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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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-2021-36380 in production — separate from our analysis above.

No notes yet

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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