Command InjectionWeakness · CWE-77

CVE-2026-9477

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 issue affects the function setAccessDeviceCfg of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. Performing a manipulation of the argument mac results in os command injection. The attack is possible to be carried out remotely. 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 · moderate confidence

OS command injection vulnerability in Totolink A8000RU router's web management interface. The setAccessDeviceCfg function in /cgi-bin/cstecgi.cgi fails to properly sanitize the 'mac' parameter, allowing attackers to inject arbitrary OS commands via the CGI interface. The vulnerability is remotely exploitable without authentication, as indicated by the critical CVSS score.

MitigationApply vendor firmware update if available; otherwise, restrict access to the router's web management interface to trusted networks or disable remote administration to reduce attack surface.

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 and check the device information page, or look for 'Totolink A8000RU' labeling on the hardware itself
    Affected if The device is a Totolink A8000RU router
  2. Confirm web interface accessibility
    Attempt to access the router's web interface (typically http://192.168.0.1 or the IP assigned to the device) and verify the cgi-bin/cstecgi.cgi endpoint is reachable
    Affected if The web management interface and cgi-bin/cstecgi.cgi are accessible from the network you are testing
  3. Verify the setAccessDeviceCfg function is present
    Send a request to cgi-bin/cstecgi.cgi with a parameter that invokes the setAccessDeviceCfg function (the 'mac' parameter is used by this function for device access control)
    Affected if The endpoint responds and accepts parameters related to device configuration including the 'mac' parameter
  4. Check firmware version
    If accessible through the web interface, navigate to the system or firmware information page to view the installed firmware version
    Affected if The installed firmware version has not been patched (compare against any available vendor firmware updates for this model)

A user is affected if they have a Totolink A8000RU router with an accessible web management interface where the cgi-bin/cstecgi.cgi endpoint accepts the 'mac' parameter in the setAccessDeviceCfg function without sanitization.

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, restrict access to the router's web management interface to trusted networks or disable remote administration to reduce attack surface.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,880
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-9477 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2026-9477 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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