Command InjectionWeakness · CWE-77

CVE-2026-9408

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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 vulnerability was detected in Totolink A8000RU 7.1cu.643_b20200521. Affected by this issue is the function setStaticDhcpRules of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. The manipulation of the argument enable results in os command injection. The attack may be performed from remote. The exploit is now public and may be used.

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

OS command injection vulnerability in Totolink A8000RU router's web management interface (cgi-bin/cstecgi.cgi). The setStaticDhcpRules function fails to sanitize the 'enable' argument, allowing remote attackers to execute arbitrary OS commands via crafted input.

MitigationPrimary mitigation is to obtain and apply vendor firmware patch when available. Immediately restrict network access to the web management interface via firewall rules or disable remote management if not required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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. Confirm device model is Totolink A8000RU
    Access the router web interface or check the device label/marketing to verify the exact model number. Alternatively, inspect DHCP lease tables or network scans for the device hostname or MAC OUI.
    Affected if The device is not a Totolink A8000RU router.
  2. Verify web management interface is accessible
    Attempt to access http://[router-ip]/cgi-bin/cstecgi.cgi from a client on the same network. A response (even an error) indicates the CGI endpoint exists.
    Affected if The cgi-bin/cstecgi.cgi endpoint is unreachable or does not exist.
  3. Check if remote web management is enabled
    Log into the router admin panel and navigate to the remote management or administrator access settings. Look for options like 'Enable Remote Management', 'Remote Access', or Web Service Ports (HTTP/HTTPS) bound to WAN interfaces.
    Affected if Remote management is disabled and the web interface is only accessible from the LAN side.
  4. Identify firmware version for comparison
    In the router admin panel, look for a 'Firmware Version', 'System Info', or 'About' page. Note the exact version string displayed.
    Affected if The installed firmware version is unknown or cannot be determined.
  5. Verify setStaticDhcpRules function availability
    Send a crafted POST request to cgi-bin/cstecgi.cgi with action=setStaticDhcpRules (or similar). A valid response with DHCP static rule configuration options indicates the function exists. Use a tool like Burp Suite or curl with appropriate headers.
    Affected if The setStaticDhcpRules function is not present in the CGI binary.

A Totolink A8000RU with an accessible cgi-bin/cstecgi.cgi endpoint, especially if remote web management is enabled, is likely affected when the setStaticDhcpRules function processes an unsanitized 'enable' parameter in system command execution.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Primary mitigation is to obtain and apply vendor firmware patch when available. Immediately restrict network access to the web management interface via firewall rules or disable remote management if not required.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
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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-2026-9408 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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