Command InjectionWeakness · CWE-77

CVE-2026-9475

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 determined in Totolink A8000RU 7.1cu.643_b20200521. This affects the function setIpQosRules of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. This manipulation of the argument Comment causes os command injection. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized.

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 (cstecgi.cgi). The setIpQosRules function fails to sanitize the Comment parameter before passing it to system commands, allowing remote authenticated attackers to execute arbitrary OS commands.

MitigationDisable remote web management access immediately; restrict management interface to trusted networks only. Contact Totolink for firmware updates or consider replacing the device if no patch is available.

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 router model
    Access the router's web management interface and check the device info/status page, or check the device label/marketing for the model name. Alternatively, inspect HTTP headers or check for Totolink-specific branding in the interface.
    Affected if The device is not a Totolink A8000RU router.
  2. Check the installed firmware version
    Log into the router web interface and navigate to System or Status settings to view the firmware version. If SSH/Telnet is enabled, run 'cat /proc/version' or check /etc/version file if accessible.
    Affected if The firmware version is 7.1cu.643_b20200521 or earlier (any version prior to a patched release).
  3. Verify the CGI interface is accessible
    Attempt to reach http://<router-ip>/cgi-bin/cstecgi.cgi via HTTP or HTTPS. A valid response indicates the web interface is active.
    Affected if The cstecgi.cgi endpoint responds, indicating the vulnerable interface is exposed.
  4. Confirm QoS functionality is present
    Check the router web interface for IP QoS, Traffic Control, or Bandwidth Control settings. Look for a feature named setIpQosRules or similar QoS rule configuration.
    Affected if QoS or traffic shaping features are enabled or accessible in the management interface.

You are affected if the device is a Totolink A8000RU running firmware 7.1cu.643_b20200521 or earlier, with the web management interface (cstecgi.cgi) accessible and the setIpQosRules QoS feature present.

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

Disable remote web management access immediately; restrict management interface to trusted networks only. Contact Totolink for firmware updates or consider replacing the device if no patch is available.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing3.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,050
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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-2026-9475 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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