Command InjectionWeakness · CWE-77

CVE-2026-7154

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-27
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 A8000RU 7.1cu.643_b20200521. This affects the function setAdvancedInfoShow of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Executing a manipulation of the argument tty_server can lead to os command injection. The attack can be launched 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 · moderate confidence

OS command injection vulnerability in Totolink A8000RU router firmware (7.1cu.643_b20200521). The setAdvancedInfoShow function in /cgi-bin/cstecgi.cgi fails to sanitize the tty_server parameter, allowing remote attackers to inject arbitrary shell commands via the CGI handler.

MitigationRestrict access to the router's web interface/CGI endpoints from untrusted networks; if available, apply vendor firmware update. If no patch exists, consider replacing the device.

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. Confirm device model is Totolink A8000RU
    Check the device label or access the router web interface and look for the model number in the status or system information page
    Affected if The device is a Totolink A8000RU router
  2. Check firmware version
    Access the router web interface, navigate to System or Status section, and locate the firmware version displayed. Compare it to version 7.1cu.643_b20200521
    Affected if Firmware version matches exactly 7.1cu.643_b20200521
  3. Verify CGI interface is exposed
    Attempt to access cstecgi.cgi via HTTP or HTTPS on the router's IP address (for example: http://<router-ip>/cstecgi.cgi)
    Affected if The CGI handler responds to requests, indicating the web interface is active
  4. Check web interface network exposure
    Determine if the router management interface (port 80/443) is accessible from untrusted networks by reviewing firewall rules or attempting external access
    Affected if The router web interface is accessible from wide-area or untrusted network segments rather than only from a trusted management VLAN

You are affected if you are running Totolink A8000RU firmware version 7.1cu.643_b20200521 and the cstecgi.cgi interface is network-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 interface/CGI endpoints from untrusted networks; if available, apply vendor firmware update. If no patch exists, consider replacing the device.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
23.0 hours of engineering $4,000
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-7154 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2026-7154 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