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Command InjectionWeakness · CWE-77

CVE-2026-6116

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-12
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 has been found in Totolink A7100RU 7.4cu.2313_b20191024. This vulnerability affects the function setDiagnosisCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. The manipulation of the argument ip leads to os command injection. Remote exploitation of the attack is possible. The exploit has been disclosed to the public 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 A7100RU router's CGI handler (/cgi-bin/cstecgi.cgi). The setDiagnosisCfg function improperly validates the 'ip' parameter, allowing remote attackers to inject and execute arbitrary operating system commands via the web interface.

MitigationApply vendor firmware update if available; otherwise, disable remote administrative access, implement network segmentation, and block external traffic to the router's web interface (ports 80/443) 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 and firmware version
    Access the router web admin panel and navigate to System Status or Firmware Upgrade page to view hardware model and firmware version. Alternatively, inspect the device label or use network fingerprinting tools like Nmap to identify the device.
    Affected if Device model is Totolink A7100RU (any firmware version, since version ranges not specified in CVE data)
  2. Confirm the web CGI interface is accessible
    Test connectivity to HTTP (port 80) and HTTPS (port 443) on the router's IP address using curl, wget, or nmap. Verify the /cgi-bin/cstecgi.cgi endpoint responds.
    Affected if The CGI handler /cgi-bin/cstecgi.cgi is reachable over the network
  3. Check if remote administrative access is enabled
    Review the router's administration settings under Firewall, Access Control, or Remote Management to determine if the web interface is exposed to WAN/untrusted networks. Look for settings like 'Enable Remote Management' or 'Allow external access'.
    Affected if Remote administrative access is enabled, allowing unauthenticated attackers on untrusted networks to reach the CGI interface
  4. Verify the setDiagnosisCfg function exists
    If possible, examine the firmware or attempt a benign request to the CGI endpoint with the setDiagnosisCfg action to confirm the function handles the 'ip' parameter. In a live system, this requires caution as it triggers the vulnerable code path.
    Affected if The setDiagnosisCfg function processes the 'ip' parameter without sanitization (the core vulnerability)

You are affected if you have a Totolink A7100RU router with the web interface (CGI handler) accessible from an untrusted network, enabling remote command injection via the ip parameter in setDiagnosisCfg.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor firmware update if available; otherwise, disable remote administrative access, implement network segmentation, and block external traffic to the router's web interface (ports 80/443) to reduce attack surface.

Recommended fix Moderate confidence

Latest available Totolink A7100RU firmware from official Totolink support (www.totolink.net)

  1. 1. Identify the current firmware version of the Totolink A7100RU router by accessing the web management interface or checking the device label.
  2. 2. Visit the official Totolink support page at www.totolink.net and navigate to the downloads/support section for the A7100RU model.
  3. 3. Download the latest stable firmware version available for the A7100RU.
  4. 4. Access the router's web administration panel and navigate to the firmware upgrade or system settings section.
  5. 5. Upload and apply the downloaded firmware file following the on-screen instructions.
  6. 6. After the upgrade completes, verify the new firmware version and confirm the device functions normally.
  7. 7. If no official firmware update is available from Totolink, consider implementing network-level filtering to block external access to the /cgi-bin/cstecgi.cgi endpoint as a mitigation.
Caveat Firmware updates may reset router configuration to defaults; backup current settings before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,150
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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-2026-6116 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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