CVE-2026-5994
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 security flaw has been discovered in Totolink A7100RU 7.4cu.2313_b20191024. This issue affects the function setTelnetCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Performing a manipulation of the argument telnet_enabled results in os command injection. The attack is possible to be carried out remotely. The exploit has been released to the public and may 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 · high confidenceOS command injection vulnerability in Totolink A7100RU router's CGI handler (cstecgi.cgi). The setTelNetCfg function fails to sanitize the telnet_enabled parameter, allowing remote attackers to inject and execute arbitrary operating system commands on 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 checksWork through these to decide whether this CVE applies to you.
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Confirm device model is Totolink A7100RUAccess the router's web interface or check the device label/marketing to verify the exact model number matches 'A7100RU'Affected if The device is a Totolink A7100RU router
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Verify CGI binary is accessibleAttempt to access the endpoint http://<router-ip>/cgi-bin/cstecgi.cgi (or /cgi/cstecgi.cgi) - the vulnerable CGI handler should respond to HTTP requestsAffected if The CGI endpoint responds, indicating the web interface is active and potentially exploitable
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Check for the vulnerable setTelNetCfg functionExamine the firmware binary (cstecgi.cgi) for the string 'setTelNetCfg' using tools like binwalk, strings, or disassemblers if firmware extraction is possibleAffected if The function name setTelNetCfg exists in the binary and processes the 'telnet_enabled' parameter without sanitization
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Verify web management interface is exposedConfirm the router's HTTP/HTTPS management interface is reachable from the network segment being assessedAffected if The web interface is accessible, allowing potential interaction with the vulnerable CGI endpoint
If the device is a Totolink A7100RU with an accessible cstecgi.cgi containing the setTelNetCfg function, the command injection flaw is present and exploitable if the telnet configuration feature processes user input without sanitization.
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 dataApply network segmentation to isolate the device; block external access to the CGI endpoint at the firewall. Since the firmware is from 2019 and likely end-of-life with no vendor patch available, consider replacing the device with a supported model.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-5994 — 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-2026-5994 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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- Version or environment caveats, and links to real fixes
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