CVE-2026-36821
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 · uneditedShenzhen Tenda Technology Co., Ltd Tenda W20E v15.11.0.6 was discovered to contain a buffer overflow in the picCropName parameter of the formCropAndSetWewifiPic function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted HTTP request.
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 confidenceA buffer overflow vulnerability exists in the picCropName parameter of the formCropAndSetWewifiPic function in Tenda W20E router firmware v15.11.0.6. Attackers can cause a Denial of Service by sending a crafted HTTP request with an overly long picCropName value that overflows the allocated buffer.
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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify the device modelAccess the router's web interface or check the device label/marketing to confirm the model is Tenda W20EAffected if The device is not a Tenda W20E router - different models are not affected by this specific vulnerability
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Check the firmware versionLog into the router web interface and navigate to System Settings > Firmware Upgrade, or use the command 'cat /proc/version' via telnet/SSH if available, to determine the installed firmware versionAffected if The firmware version is v15.11.0.6 - this is the specific version containing the vulnerability
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Verify the web management interface is enabledCheck router settings under System Settings > Remote Management, or attempt to access http://[router-ip]/ from the networkAffected if The web interface is enabled and accessible on the local network or remotely - this is required for the attack vector
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Confirm the vulnerable function existsAnalyze the firmware binary for the function 'formCropAndSetWewifiPic' and parameter 'picCropName', or inspect HTTP responses from the router's web interface for camera/wifi customization featuresAffected if The router firmware contains the formCropAndSetWewifiPic function handling the picCropName parameter - the vulnerability exists in this specific function
The user is affected if they are running Tenda W20E router firmware version 15.11.0.6 with the web interface enabled and the vulnerable picCropName parameter present in the formCropAndSetWewifiPic function.
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 vendor firmware patches when available. If no patch exists, restrict network access to the router's web interface and consider replacing the device.
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-36821 — 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-2026-36821 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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- 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
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