Command InjectionWeakness · CWE-77

CVE-2026-7139

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-27
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 flaw has been found in Totolink A8000RU 7.1cu.643_b20200521. This issue affects the function setWiFiAclRules of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. This manipulation of the argument mode causes os command injection. The attack is possible to be carried out remotely. The exploit has been published 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 CGI handler (cstecgi.cgi). The setWiFiAclRules function fails to sanitize the 'mode' argument before passing it to system(), allowing remote attackers to execute arbitrary commands. The flaw is remotely exploitable and has a public exploit.

MitigationRestrict network access to the router's management interface; disable remote administration if not needed; contact Totolink for firmware patch; monitor for indicators of compromise.

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
    Log into the router web interface or check the device label to confirm the model is Totolink A8000RU
    Affected if Device is a Totolink A8000RU router
  2. Check the installed firmware version
    In the router web interface, navigate to System > Firmware or Status page to view the firmware version. Compare against any Totolink security advisories for CVE-2026-7139
    Affected if Firmware version is unpatched for this vulnerability
  3. Verify CGI interface accessibility
    Attempt to access http://[router-ip]/cstecgi.cgi - the vulnerability is in this CGI handler
    Affected if The cstecgi.cgi endpoint is reachable from the network
  4. Confirm if remote management is enabled
    In the router web interface, check System > Administration > Remote Management to see if remote access via WAN is enabled
    Affected if Remote management is enabled and the web interface is exposed to untrusted networks
  5. Look for indicators of compromise
    Review router configuration for unauthorized WiFi ACL rules, check for unexpected admin accounts, and monitor network traffic for suspicious command injection payloads
    Affected if Unexpected WiFi ACL rules, new admin accounts, or unusual outbound connections are detected

A Totolink A8000RU router with unpatched firmware where the cstecgi.cgi interface is network-accessible is vulnerable to remote command injection via the WiFi ACL mode parameter.

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

Restrict network access to the router's management interface; disable remote administration if not needed; contact Totolink for firmware patch; monitor for indicators of compromise.

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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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-2026-7139 in production — separate from our analysis above.

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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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