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Command InjectionWeakness · CWE-77

CVE-2026-5688

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 security vulnerability has been detected in Totolink A7100RU 7.4cu.2313_b20191024. Impacted is the function setDdnsCfg of the file /cgi-bin/cstecgi.cgi. Such manipulation of the argument provider leads to os command injection. The attack may be launched remotely. The exploit has been disclosed publicly 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 the setDdnsCfg function of /cgi-bin/cstecgi.cgi on Totolink A7100RU firmware 7.4cu.2313_b20191024. The 'provider' parameter in DDNS configuration is not sanitized before being passed to system commands, allowing remote attackers to execute arbitrary OS commands via crafted requests.

MitigationRestrict access to the router's web administration interface (e.g., via firewall or VLAN) to limit exposure; contact Totolink for a firmware patch or consider device replacement if no patch is available.

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. Identify device model
    Access the router web interface or check the device label/marketing to confirm it is a Totolink A7100RU model router.
    Affected if The device is not a Totolink A7100RU router.
  2. Check firmware version
    Log into the router web interface and navigate to the Status or System Information page to view the firmware version. Alternatively, check the /cgi-bin/cstecgi.cgi banner or sysinfo if accessible via CLI or firmware extraction.
    Affected if The firmware version is 7.4cu.2313_b20191024.
  3. Verify DDNS functionality is enabled
    In the router web interface, navigate to the DDNS settings page (usually under Advanced or Network settings). Check if any DDNS provider is configured and enabled.
    Affected if DDNS is configured and the setDdnsCfg function is accessible.
  4. Confirm web interface accessibility
    Attempt to access http://[router-ip]/cgi-bin/cstecgi.cgi from a browser. The vulnerability requires the web interface to be reachable.
    Affected if The cgi-bin/cstecgi.cgi endpoint is reachable and responds to requests.

You are affected if you are running a Totolink A7100RU router with firmware version 7.4cu.2313_b20191024, the DDNS feature is enabled, and the router web interface is accessible.

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 access to the router's web administration interface (e.g., via firewall or VLAN) to limit exposure; contact Totolink for a firmware patch or consider device replacement if no patch is available.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2026-5688 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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