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Command InjectionWeakness · CWE-77

CVE-2026-5996

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-10
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 security vulnerability has been detected in Totolink A7100RU 7.4cu.2313_b20191024. The affected element is the function setAdvancedInfoShow of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. The manipulation of the argument tty_server leads to os command injection. It is possible to initiate the attack 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 Totolink A7100RU router firmware where the setAdvancedInfoShow function in /cgi-bin/cstecgi.cgi fails to sanitize the tty_server parameter before passing it to system shell, allowing remote attackers to execute arbitrary commands with elevated privileges.

MitigationApply vendor firmware patch when available; until then, disable remote web management access or place device behind a firewall to block external access to the CGI interface.

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
    Check the router label or access the admin web interface to confirm the model is Totolink A7100RU
    Affected if The device is not a Totolink A7100RU router (not affected)
  2. Check the firmware version
    Access the router admin panel (typically http://192.168.0.1) and navigate to System Status or Firmware Upgrade page to view the installed firmware version; compare against 7.4cu.2313_b20191024
    Affected if Firmware version is exactly 7.4cu.2313_b20191024 (affected)
  3. Verify the CGI handler exists
    Attempt to access http://<router-ip>/cgi-bin/cstecgi.cgi via HTTP request and confirm the endpoint responds (even if with an error)
    Affected if The cstecgi.cgi endpoint is not reachable (not affected)
  4. Check if remote web administration is enabled
    In the router admin panel, go to Management > Remote Management or similar setting; confirm whether remote access to the web interface from WAN is enabled
    Affected if Remote web administration is enabled and the device is directly exposed to untrusted networks (higher exposure/risk)

A user is affected if they 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 web management access or place device behind a firewall to block external access to the CGI interface.

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-2026-5996 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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data