dbcve.org
Command InjectionWeakness · CWE-77

CVE-2026-5691

HIGH · 7.3 CVSS v3.1 Published 2026-04-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
82/100
Remediation priority · High
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 affects the function setFirewallType of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument firewallType leads to os command injection. The attack is possible to be carried out remotely. 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 firmware 7.4cu.2313_b20191024. The setFirewallType function in /cgi-bin/cstecgi.cgi does not properly sanitize the firewallType parameter before passing it to system commands, allowing remote attackers to execute arbitrary OS commands.

MitigationApply vendor firmware update if available; otherwise restrict access to the web interface via network segmentation or firewall rules to limit exposure to trusted users only.

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
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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. Confirm device model is Totolink A7100RU
    Access the router web interface and check the system status page, or use network reconnaissance to identify the device via MAC OUI, HTTP headers, or firmware fingerprint. Alternatively, check the device label or admin console for model number.
    Affected if The device is NOT a Totolink A7100RU router (different models are not affected by this specific CVE).
  2. Identify firmware version
    Log into the router admin panel and navigate to System > Firmware Upgrade or Status page to view the installed firmware version. If unavailable via UI, attempt to extract firmware via TFTP/FTP if enabled, or check the vendor download page for version numbering.
    Affected if Firmware version cannot be determined, but the device is confirmed as A7100RU and the web interface is accessible.
  3. Verify CGI interface is reachable
    Attempt to access or send a request to /cgi-bin/cstecgi.cgi on the router's IP address. This can be done with: curl -X POST http://<router-ip>/cgi-bin/cstecgi.cgi -d '{"topicurl":"setFirewallType"}' or similar probe.
    Affected if The CGI endpoint is unreachable from your testing location (this does NOT mean unaffected, only that you cannot test from your current network position).
  4. Check if remote web management is enabled
    Log into the router admin panel and navigate to System > Administration or Security settings. Look for 'Remote Management', 'Remote Web Management', or 'Allow WAN Access' options. Verify if the web interface is accessible from outside the local network.
    Affected if Remote web management/WAN access to the admin interface is ENABLED, making the CGI interface reachable from external networks.
  5. Test firewallType parameter handling (if authorized)
    If you have explicit authorization to test your own device, send a crafted request to the CGI endpoint with a test payload in the firewallType parameter (e.g., firewallType=;echo vulnerable). Observe if command injection occurs in the response.
    Affected if The device executes OS commands injected through the firewallType parameter (indicates vulnerability present).

The device is affected if it is a Totolink A7100RU router with an accessible cgi-bin/cstecgi.cgi interface and the setFirewallType function is present in the firmware, especially if remote web management is enabled.

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 if available; otherwise restrict access to the web interface via network segmentation or firewall rules to limit exposure to trusted users only.

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-2026-5691 in production — separate from our analysis above.

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