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Classic Buffer OverflowWeakness · CWE-120

CVE-2026-51380

CRITICAL · 9.8 CVSS v3.1 Published 2026-07-15
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 5 weeks old

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
Buffer Overflow vulnerability in Tenda AC10 v3 (firmware V03.03.16.09) allows attackers to cause a permanent Denial of Service (DoS) or potentially execute remote code via the /cgi-bin/UploadCfg endpoint

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

A buffer overflow vulnerability exists in the /cgi-bin/UploadCfg endpoint of Tenda AC10 v3 routers running firmware V03.03.16.09. The endpoint handles configuration file uploads without proper bounds checking, allowing attackers to overflow the buffer and potentially achieve remote code execution or cause a permanent denial of service.

MitigationApply the latest firmware update from Tenda if available; if no update exists, restrict administrative access to the /cgi-bin/UploadCfg endpoint via firewall rules or disable remote administration entirely.

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
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
    Access the router admin interface or check the device label to confirm the model is Tenda AC10 v3
    Affected if The device is a Tenda AC10 v3 router
  2. Check the installed firmware version
    Log into the router admin interface and navigate to System Settings or Administration to view the firmware version; alternatively, check via telnet/SSH if enabled
    Affected if The firmware version is V03.03.16.09
  3. Verify if the /cgi-bin/UploadCfg endpoint is accessible
    Attempt to access http://[router-ip]/cgi-bin/UploadCfg or check if the CGI binary exists on the device filesystem via telnet/SSH
    Affected if The endpoint responds or the CGI script is present on the device
  4. Confirm if remote administration is enabled
    Check the router admin interface under Remote Management or Access Control settings to see if remote HTTP/HTTPS admin access is enabled
    Affected if Remote administration is enabled and the router is accessible from the WAN interface

You are affected if you have a Tenda AC10 v3 router running firmware V03.03.16.09 with the /cgi-bin/UploadCfg endpoint accessible, especially if remote administration is enabled.

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 the latest firmware update from Tenda if available; if no update exists, restrict administrative access to the /cgi-bin/UploadCfg endpoint via firewall rules or disable remote administration entirely.

Have this fixed 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
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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-2026-51380 in production — separate from our analysis above.

No notes yet

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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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