W20e FirmwareOperating system · Tenda

CVE-2026-24109

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 exploit the vulnerability by controlling the value of `picName`. When this value is used in `sprintf` without validating variable sizes, it could lead to a buffer overflow vulnerability.

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 · moderate confidence

Buffer overflow vulnerability in Tenda W20E V4.0br_V15.11.0.6 router firmware where the `picName` parameter is used in an unsanitized `sprintf` call, allowing remote attackers to overflow a buffer by providing an arbitrarily long string value.

MitigationApply vendor firmware update when available; otherwise implement strict input length validation on the `picName` parameter before the sprintf call to enforce proper buffer bounds.

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. Identify device model
    Check the router model through web interface (typically at http://192.168.0.1), system status page, or label on device
    Affected if Device is not a Tenda W20E router
  2. Check firmware version
    Access router web interface, navigate to System Settings or Status page to view firmware version, or use command line: cat /proc/version if telnet/ssh is enabled
    Affected if Firmware version is 15.11.0.6
  3. Verify picName parameter feature accessibility
    Check if the router web interface exposes any functionality that accepts a picName parameter, such as image upload, banner configuration, or logo settings (typically under Advanced, Network, or System settings)
    Affected if The picName parameter accepting feature is accessible from LAN or WAN interface
  4. Look for indicators of exploitation
    Review router logs for unusual patterns, check for unexpected new files in /var or /tmp directories, or look for unexpected changes to configuration files
    Affected if Unexpected modifications found or logs show abnormal sprintf/format string errors

The device is affected only if it is a Tenda W20E router running firmware version 15.11.0.6 and the picName parameter functionality is 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

Apply vendor firmware update when available; otherwise implement strict input length validation on the `picName` parameter before the sprintf call to enforce proper buffer bounds.

Fix this in W20e Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2026-24109 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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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