N300rh FirmwareOperating system · Totolink

CVE-2026-3301

CRITICAL · 9.8 CVSS v3.1 Published 2026-02-27
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
Public exploit 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 flaw has been discovered in Totolink N300RH 6.1c.1353_B20190305. Affected by this vulnerability is the function setWebWlanIdx of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. Performing a manipulation of the argument webWlanIdx results in os command injection. The attack can be initiated 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 confidence

OS command injection vulnerability in Totolink N300RH router's web management interface (cstecgi.cgi). The setWebWlanIdx function fails to sanitize the webWlanIdx parameter before passing it to a system call, allowing remote attackers to execute arbitrary OS commands with root privileges. Public exploit available.

MitigationApply vendor firmware update when available. Until then, disable remote web management interface access from WAN and restrict administrative access to trusted networks only.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
N300rh FirmwareOperating system
Affected:= 6.1c.1349_b20181018= 6.1c.1353_b20190305

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 router model
    Check the device label or login to the web interface and look for the model number (N300RH) in the system information or status page
    Affected if The device is not a Totolink N300RH router - this vulnerability only affects that specific model
  2. Check the firmware version
    Access the router's web management interface, navigate to System Status or Firmware Upgrade section, and locate the firmware version information. Compare it against the affected versions: 6.1c.1349_b20181018 or 6.1c.1353_b20190305
    Affected if The installed firmware version exactly matches one of the two affected versions listed (6.1c.1349_b20181018 or 6.1c.1353_b20190305)
  3. Verify web management interface accessibility
    Attempt to access the router's web interface from the network where the router is deployed. Check if the cstecgi.cgi endpoint is reachable by accessing http://<router-ip>/cstecgi.cgi
    Affected if The web management interface (specifically the cstecgi.cgi endpoint) is accessible from the network you are testing from
  4. Confirm setWebWlanIdx function availability
    Send a request to the cstecgi.cgi endpoint with the setWebWlanIdx action and a test webWlanIdx parameter value to see if the function accepts and processes it
    Affected if The setWebWlanIdx function responds to requests and processes the webWlanIdx parameter without proper validation

You are affected if you have a Totolink N300RH router running firmware version 6.1c.1349_b20181018 or 6.1c.1353_b20190305, and the web management interface with the cstecgi.cgi endpoint is accessible and the setWebWlanIdx function accepts the webWlanIdx parameter.

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 update when available. Until then, disable remote web management interface access from WAN and restrict administrative access to trusted networks only.

Fix this in N300rh Firmware 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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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-2026-3301 in production — separate from our analysis above.

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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
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