Command InjectionWeakness · CWE-77

CVE-2026-5975

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-09
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 identified in Totolink A7100RU 7.4cu.2313_b20191024. The impacted element is the function setDmzCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Such manipulation of the argument wanIdx leads to os command injection. The attack may be performed from remote. The exploit is publicly available and might 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 A7100RU router firmware 7.4cu.2313_b20191024. The setDmzCfg function in /cgi-bin/cstecgi.cgi fails to sanitize the wanIdx parameter before passing it to system shell commands, allowing unauthenticated remote attackers to execute arbitrary OS commands.

MitigationApply vendor firmware patch when available. Until then, disable remote administration interfaces, restrict network access to the device, and monitor for indicators of compromise. Consider network segmentation to limit exposure.

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 interface or check the device label to confirm it is a Totolink A7100RU router
    Affected if The device is not a Totolink A7100RU model
  2. Check the firmware version
    Log into the router web interface and navigate to the status or system information page to find the firmware version, or use the command: cat /proc/version if you have shell access
    Affected if The firmware version is 7.4cu.2313_b20191024 or earlier
  3. Verify the vulnerable CGI binary exists
    If you have shell access, check for the existence of /cgi-bin/cstecgi.cgi by running: ls -la /cgi-bin/cstecgi.cgi
    Affected if The file /cgi-bin/cstecgi.cgi does not exist or is not accessible
  4. Check if the DMZ configuration interface is exposed
    Access the router web interface and verify if the DMZ settings page is accessible at the default administration URL, typically http://<router-ip>/cgi-bin/cstecgi.cgi
    Affected if The DMZ configuration interface is accessible without additional network restrictions
  5. Verify network exposure of the management interface
    Check if the router web interface (port 80/443) is exposed to the internet by scanning external interfaces: nmap -p 80,443 <router-external-ip>
    Affected if The router administration interface is reachable from untrusted networks such as the internet

You are affected if you have a Totolink A7100RU router running firmware version 7.4cu.2313_b20191024 with the web interface accessible to attackers.

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 patch when available. Until then, disable remote administration interfaces, restrict network access to the device, and monitor for indicators of compromise. Consider network segmentation to limit exposure.

Have this fixed Scoped from the published advisory
  • Consultation6.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,520
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2026-5975 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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