dbcve.org
W20e FirmwareOperating system · Tenda

CVE-2026-24110

CRITICAL · 9.8 CVSS v3.1 Published 2026-03-02
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
An issue was discovered in Tenda W20E V4.0br_V15.11.0.6. Attackers may send overly long `addDhcpRules` data. When these rules enter the `addDhcpRule` function and are processed by `ret = sscanf(pRule, " %d\t%[^\t]\t%[^\n\r\t]", &dhcpsIndex, dhcpsIP, dhcpsMac);`, the lack of size validation for the rules could lead to buffer overflows in `dhcpsIndex`, `dhcpsIP`, and `dhcpsMac`.

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

Buffer overflow vulnerability in Tenda W20E V4.0br_V15.11.0.6's addDhcpRule function. The sscanf call lacks size parameters (%[^ ] and %[^ ]), allowing attackers to overflow dhcpsIP and dhcpsMac buffers via overly long addDhcpRules input. This can lead to remote code execution with critical severity (CVSS 9.8).

MitigationImplement size limits in the sscanf format string (e.g., %31s for a 32-byte buffer) and add input length validation before processing DHCP rule data to prevent buffer overflows.

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
W20e FirmwareOperating system
Affected:= 15.11.0.6

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. Confirm Tenda W20E model
    Access the device web interface or check the device label/metadata to verify the model is W20E
    Affected if Device model is not Tenda W20E
  2. Check firmware version
    Navigate to the device web interface System Status or firmware upgrade page to display the firmware version; alternatively, extract and analyze the firmware binary
    Affected if Firmware version is not 15.11.0.6
  3. Verify web management interface is accessible
    Attempt to access the device HTTP/HTTPS management interface on the LAN or WAN IP address
    Affected if Web interface is not accessible and the addDhcpRule function cannot be reached
  4. Confirm DHCP feature is enabled
    Navigate to the DHCP settings page in the web interface or inspect HTTP requests to the addDhcpRule function endpoint
    Affected if DHCP rule configuration feature is disabled or not present in the interface

Device is affected if it is a Tenda W20E running firmware version 15.11.0.6 with the web management interface and DHCP configuration feature accessible.

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

Implement size limits in the sscanf format string (e.g., %31s for a 32-byte buffer) and add input length validation before processing DHCP rule data to prevent buffer overflows.

Fix this in W20e Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-24110 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-24110 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