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Command InjectionWeakness · CWE-77

CVE-2026-9433

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 weakness has been identified in Totolink A8000RU 7.1cu.643_b20200521. This issue affects the function setMacFilterRules of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. This manipulation of the argument enable causes os command injection. The attack may be initiated remotely. The exploit has been made available to the public and could 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 the setMacFilterRules function of Totolink A8000RU router's web management interface (/cgi-bin/cstecgi.cgi). The enable argument is not properly sanitized before being passed to an OS command, allowing remote attackers to execute arbitrary commands on the underlying system.

MitigationApply vendor firmware update when available; until then, disable remote access to the web management interface or place the device behind a firewall with restricted access.

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 web management interface and check the device information page, or log into the device via SSH/Telnet and run 'cat /proc/cpuinfo' or 'cat /etc/version' to confirm the model is Totolink A8000RU
    Affected if The device is not a Totolink A8000RU router, then this specific CVE does not apply
  2. Check the firmware version
    In the router web interface, navigate to System Status or Firmware Upgrade page to view the current firmware version; alternatively, via CLI run 'cat /etc/version' or check the banner on login
    Affected if The firmware version is 7.1cu.643_b20200521 or other unpatched versions within the same release line
  3. Verify the vulnerable CGI endpoint exists
    Attempt to access the URI /cgi-bin/cstecgi.cgi on the router's web server (e.g., http://<router-ip>/cgi-bin/cstecgi.cgi); a 200 response or authentication prompt indicates the endpoint is present
    Affected if The endpoint returns a 404 or is unreachable, the vulnerability cannot be exploited
  4. Confirm remote web management is enabled
    In the router web interface, go to Administration > Remote Management or similar section and check if remote access to the web interface is enabled for WAN/outside networks
    Affected if Remote management is disabled and the web interface is only accessible from LAN, the attack surface is significantly reduced
  5. Inspect mac filter rules configuration
    Navigate to Wireless > MAC Filter or Access Control in the web interface and examine the current mac filter rule configuration
    Affected if The mac filter feature is in use, the setMacFilterRules function is likely invoked and the vulnerable parameter can be manipulated

A user is affected if they are running Totolink A8000RU firmware version 7.1cu.643_b20200521 with the web management interface accessible (especially from remote networks) and the cgi-bin/cstecgi.cgi endpoint is present and functional.

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 when available; until then, disable remote access to the web management interface or place the device behind a firewall with restricted access.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2026-9433 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
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  • Version or environment caveats, and links to real fixes
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