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Command InjectionWeakness · CWE-77

CVE-2026-9405

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 security flaw has been discovered in Totolink A8000RU 7.1cu.643_b20200521. This impacts the function setGameSpeedCfg of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. Performing a manipulation of the argument enable results in os command injection. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks.

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. The setGameSpeedCfg function in /cgi-bin/cstecgi.cgi fails to sanitize the 'enable' parameter, allowing remote attackers to inject and execute arbitrary OS commands via the CGI interface.

MitigationApply vendor firmware update if available; otherwise, disable remote web management access or restrict administrative interface to trusted networks via firewall rules to prevent unauthenticated exploitation.

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. Identify the device model
    Access the router's web management interface or check the device label/ admin page to confirm the model is Totolink A8000RU
    Affected if The device is a Totolink A8000RU router
  2. Check the installed firmware version
    In the router web interface, navigate to System Status or Firmware Upgrade page to view the current firmware version. Compare against 7.1cu.643_b20200521
    Affected if The firmware version matches 7.1cu.643_b20200521 or falls within the same release branch without vendor patching
  3. Verify the vulnerable CGI endpoint exists
    Attempt to access http://<router-ip>/cgi-bin/cstecgi.cgi via HTTP request. A response (even an error) indicates the endpoint is present
    Affected if The /cgi-bin/cstecgi.cgi endpoint responds and is reachable from the network
  4. Confirm web management is remotely accessible
    Check router firewall or access settings to determine if the web interface (port 80/443) is accessible from outside the local network, or test remote connectivity to the router IP
    Affected if The router's web management interface is accessible from untrusted networks (WAN side)

The device is affected if it is a Totolink A8000RU running firmware 7.1cu.643_b20200521 with the cstecgi.cgi endpoint accessible, especially if web management is exposed to untrusted networks.

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

Apply vendor firmware update if available; otherwise, disable remote web management access or restrict administrative interface to trusted networks via firewall rules to prevent unauthenticated exploitation.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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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-2026-9405 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
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