CVE-2026-6139
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 · uneditedA vulnerability has been found in Totolink A7100RU 7.4cu.2313_b20191024. This affects the function UploadOpenVpnCert of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Such manipulation of the argument FileName leads to os command injection. The attack can be launched 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 confidenceOS command injection vulnerability in Totolink A7100RU router firmware 7.4cu.2313_b20191024. The CGI handler function UploadOpenVpnCert in /cgi-bin/cstecgi.cgi does not properly sanitize the FileName argument, allowing remote attackers to execute arbitrary operating system commands.
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 checksWork through these to decide whether this CVE applies to you.
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Identify the router modelAccess the router web administration interface (typically at 192.168.0.1 or 192.168.1.1) and check the device status or system information page to confirm the model is Totolink A7100RUAffected if The device model is Totolink A7100RU
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Check the firmware versionIn the router web interface, navigate to System or Firmware status to find the installed firmware version; alternatively, check the startup banner or kernel message via telnet/SSH if availableAffected if The firmware version is 7.4cu.2313_b20191024
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Verify the vulnerable CGI binary existsAttempt to access the file /cgi-bin/cstecgi.cgi on the router via HTTP request (e.g., curl http://<router-ip>/cgi-bin/cstecgi.cgi)Affected if The CGI binary exists and responds to requests
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Confirm OpenVPN feature is enabledCheck the router web interface for OpenVPN server or client configuration settings under VPN or Network settings; the vulnerable function UploadOpenVpnCert processes VPN certificate uploadsAffected if OpenVPN functionality is present or enabled on the device
You are affected if you have a Totolink A7100RU router running firmware version 7.4cu.2313_b20191024 with the /cgi-bin/cstecgi.cgi binary present and OpenVPN features accessible.
Generated from the published advisory. Verify against your own configuration.
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 dataSince this is an older device with no indicated vendor patch, immediately restrict administrative interface access to trusted networks only; consider network segmentation or replacement if vendor updates are unavailable.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-6139 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-6139 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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