W9 FirmwareOperating system · Tenda

CVE-2024-0540

CRITICAL · 9.8 CVSS v3.1 Published 2024-01-15
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 was found in Tenda W9 1.0.0.7(4456). It has been classified as critical. Affected is the function formOfflineSet of the component httpd. The manipulation of the argument ssidIndex leads to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. VDB-250710 is the identifier assigned to this vulnerability. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.

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

Stack-based buffer overflow in Tenda W9 router httpd web server. The formOfflineSet function fails to properly validate the ssidIndex argument before copying it to a fixed-size stack buffer, allowing remote attackers to overwrite return addresses and execute arbitrary code.

MitigationApply vendor firmware patch when available; otherwise isolate device behind firewall, disable remote management interfaces, or replace affected hardware. CVSS 9.8 indicates immediate exploitation risk.

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
W9 FirmwareOperating system
Affected:= 1.0.0.7\(4456\)

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 device model
    Access the router admin panel (typically at 192.168.0.1) or check the device label/marketing materials to confirm the model is Tenda W9.
    Affected if The device is not a Tenda W9 router, then it is not affected by this specific CVE.
  2. Check installed firmware version
    Log into the router web interface, navigate to System Settings or Administration section, and locate the firmware version information. Alternatively, check the firmware file if you have direct access to it.
    Affected if The firmware version is exactly 1.0.0.7(4456), then the device is affected. If the version differs (higher or lower), the device may not be vulnerable to this specific CVE.
  3. Verify httpd web server is running
    Attempt to access the router login page via HTTP (port 80) or HTTPS (port 443) from a client on the network. The vulnerability exists in the httpd service.
    Affected if The router web interface is unreachable, the vulnerable service may not be active, though this does not guarantee safety.
  4. Confirm remote management exposure
    Check router settings for "Remote Management," "Remote Access," or "WAN Access" options. Determine if the httpd service is accessible from the WAN/internet side (outside the local network).
    Affected if Remote management is enabled and the httpd service is exposed to the internet, the device is at higher risk for remote exploitation.

A Tenda W9 router running firmware version 1.0.0.7(4456) with the httpd web server accessible (especially from remote networks) is likely affected by this CVE.

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; otherwise isolate device behind firewall, disable remote management interfaces, or replace affected hardware. CVSS 9.8 indicates immediate exploitation risk.

Fix this in W9 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2024-0540 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-0540 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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