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Command InjectionWeakness · CWE-77

CVE-2026-5977

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 weakness has been identified in Totolink A7100RU 7.4cu.2313_b20191024. This impacts the function setWiFiBasicCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Executing a manipulation of the argument wifiOff can lead to os command injection. It is possible to launch the attack remotely. The exploit has been made available to the public and could be used for attacks.

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

The Totolink A7100RU router firmware contains an OS command injection vulnerability in the CGI binary (/cgi-bin/cstecgi.cgi). The setWiFiBasicCfg function fails to sanitize user input passed via the wifiOff parameter, allowing an attacker to inject arbitrary shell commands. Since this is a CGI handler processing HTTP requests, the injected commands execute with the privileges of the web server process.

MitigationImmediately restrict access to the router's web interface from untrusted networks (block external access to ports 80/443). Contact Totolink for an urgent firmware patch; if unavailable, consider replacing the device as embedded firmware vulnerabilities cannot be mitigated through configuration changes.

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 device model
    Log into the router web administration panel and check the status or system information page for the model number. Alternatively, check the device label or packaging.
    Affected if The device is NOT a Totolink A7100RU router (different models are not affected by this specific CVE)
  2. Check installed firmware version
    In the router web interface, navigate to System > Firmware Upgrade or System Status page and record the firmware version string displayed (such as 7.4cu.2313_b20191024).
    Affected if The installed firmware version is 7.4cu.2313_b20191024 exactly, or falls within the 7.4cu.2313 release line (the only known affected version per this CVE)
  3. Verify vulnerable CGI endpoint exists
    Attempt to access http://<router-ip>/cgi-bin/cstecgi.cgi via a web browser or curl command. A successful HTTP 200 response indicates the CGI interface is present.
    Affected if The /cgi-bin/cstecgi.cgi endpoint returns a valid response (the command injection cannot occur if this binary does not exist)
  4. Check if web management is remotely accessible
    From an external network (not connected to router LAN), attempt to access the router login page at the public IP. Check router settings under Advanced > Remote Management or Access Control to see if remote web management (HTTP/HTTPS from WAN) is enabled.
    Affected if Remote web management is enabled and the router is directly accessible from the internet (this is the attack surface for remote exploitation)
  5. Confirm WiFi Basic configuration function is exposed
    Send a POST request to /cgi-bin/cstecgi.cgi with a JSON body containing {"topicurl":"setWiFiBasicCfg"}. A valid response (rather than a 404 error) indicates the function is implemented and potentially reachable.
    Affected if The setWiFiBasicCfg function responds to requests (the command injection vulnerability exists in this specific function)

You are affected if you are running Totolink A7100RU firmware version 7.4cu.2313_b20191024 with the cstecgi.cgi interface accessible remotely.

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

Immediately restrict access to the router's web interface from untrusted networks (block external access to ports 80/443). Contact Totolink for an urgent firmware patch; if unavailable, consider replacing the device as embedded firmware vulnerabilities cannot be mitigated through configuration changes.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation24.0 h
  • Testing8.0 h
  • Review / QA4.0 h
40.0 hours of engineering $7,040
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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-2026-5977 in production — separate from our analysis above.

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