Command InjectionWeakness · CWE-77

CVE-2026-7240

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-28
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 vulnerability has been found in Totolink A8000RU 7.1cu.643_b20200521. This vulnerability affects the function setVpnAccountCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Such manipulation of the argument User leads to os command injection. The attack can be executed 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 A8000RU router firmware. The setVpnAccountCfg function in /cgi-bin/cstecgi.cgi accepts user input through the User parameter without proper sanitization, allowing remote attackers to execute arbitrary OS commands on the device with the privileges of the web server process.

MitigationApply vendor firmware patch when available; immediately restrict access to the router's web management interface from untrusted networks. If patch unavailable, consider network segmentation or device replacement.

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
    Access the router web management interface and check the device information page, or check the device label/packaging. Alternatively, make a GET request to the router's IP and examine the HTTP Server header or login page for Totolink branding.
    Affected if The device is a Totolink A8000RU router.
  2. Verify the vulnerable CGI endpoint exists
    Make an HTTP request to http://<router-ip>/cgi-bin/cstecgi.cgi and check for a valid response (200 OK or similar). The existence of this binary indicates the potentially vulnerable code is present.
    Affected if The /cgi-bin/cstecgi.cgi endpoint responds to requests, indicating the vulnerable firmware component is installed.
  3. Check if the web management interface is externally accessible
    Determine if the router's HTTP/HTTPS ports (typically 80/443) are reachable from untrusted networks by scanning the router's public IP or reviewing firewall rules.
    Affected if The router's web interface is exposed to untrusted networks, allowing remote attackers to reach the vulnerable endpoint.
  4. Inspect firmware version if accessible
    If you can access the router admin panel, navigate to System or Status settings to view the installed firmware version. Compare against any vendor release notes.
    Affected if The installed firmware version has not been patched to address the command injection vulnerability in setVpnAccountCfg.

You are affected if you operate a Totolink A8000RU router with the vulnerable cstecgi.cgi endpoint exposed to network access, regardless of firmware version, since no specific patched version range was provided.

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; immediately restrict access to the router's web management interface from untrusted networks. If patch unavailable, consider network segmentation or device replacement.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2026-7240 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