Command InjectionWeakness · CWE-77

CVE-2026-6113

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-12
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. Affected by this vulnerability is the function setTtyServiceCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Such manipulation of the argument ttyEnable leads to os command injection. The attack can 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 Totolink A7100RU router firmware. The setTtyServiceCfg function in /cgi-bin/cstecgi.cgi does not sanitize the ttyEnable parameter before passing it to system commands, allowing remote attackers to execute arbitrary OS commands.

MitigationApply vendor firmware patch when available. Until then, restrict network access to the CGI endpoint, disable the tty service if not required, or place the device behind a firewall with strict access controls.

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
    Access the router web interface (typically 192.168.0.1 or 192.168.1.1) and check the status or system info page for the model number, or look for 'Totolink A7100RU' labeling on the physical device.
    Affected if The device is not a Totolink A7100RU router (if different model, this specific CVE does not apply).
  2. Check for the vulnerable CGI binary
    Attempt to access the URL /cgi-bin/cstecgi.cgi on the router (e.g., http://192.168.x.x/cgi-bin/cstecgi.cgi). A 400 or 405 error typically indicates the binary exists but requires POST requests. A 404 indicates it may not be present.
    Affected if The CGI binary /cgi-bin/cstecgi.cgi is not found (the vulnerability cannot exist without this binary).
  3. Determine firmware version
    Check the router web interface for a firmware version (usually under System, Administration, or Status pages), or examine the firmware file if extracted from the device.
    Affected if Unable to determine firmware version for comparison; all unpatched A7100RU firmware versions are considered affected based on the vulnerability description.
  4. Verify tty service functionality is accessible
    Log into the router web interface and navigate to the tty or serial/terminal service settings (often under Network, Advanced, or System settings). Check if a ttyEnable or similar tty service configuration option exists.
    Affected if The tty service configuration feature is not present or not accessible in the web interface (the vulnerability requires this feature to be configurable).

The device is affected if it is a Totolink A7100RU router with the /cgi-bin/cstecgi.cgi binary present and the tty service configuration feature accessible in the firmware.

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, restrict network access to the CGI endpoint, disable the tty service if not required, or place the device behind a firewall with strict access controls.

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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Scan for this in your stack

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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-2026-6113 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
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