CVE-2024-3909
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 · uneditedA vulnerability classified as critical was found in Tenda AC500 2.0.1.9(1307). Affected by this vulnerability is the function formexeCommand of the file /goform/execCommand. The manipulation of the argument cmdinput leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-261145 was 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 · moderate confidenceA stack-based buffer overflow vulnerability exists in the formexeCommand function of Tenda AC500 routers (firmware 2.0.1.9). The function processes the cmdinput parameter without proper bounds checking, allowing an attacker to overflow the stack and potentially execute arbitrary code remotely.
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= 2.0.1.9\(1307\)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 checksWork through these to decide whether this CVE applies to you.
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Identify the router modelCheck the device label or access the router web interface to confirm it is a Tenda AC500 modelAffected if Device is not a Tenda AC500 router - this CVE only affects that specific model
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Check the firmware versionAccess the router admin interface (typically at 192.168.0.1) and navigate to System Settings > Firmware Upgrade or similar, or use the command 'cat /proc/version' via telnet/SSH if available, to determine the installed firmware versionAffected if Firmware version is 2.0.1.9(1307) - only this exact version is listed as affected
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Verify if the web management interface is exposedCheck router firewall settings to determine if the HTTP service (port 80) on the WAN interface is accessible from external networks, or attempt to access http://<wan-ip>/goform/ to confirm endpoint accessibilityAffected if The /goform/* endpoints are reachable from the WAN (external) side - the vulnerability is exploitable remotely only if the management interface is externally exposed
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Confirm remote management is enabledIn the router web interface, look for 'Remote Management', 'Remote Access', or 'Web Management' settings under Advanced or Security sections, and check if remote administration from WAN is permittedAffected if Remote management/WAN access to the web interface is enabled - this is required for remote exploitation of this vulnerability
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Check for signs of exploitationReview router system logs for unusual requests to /goform/* endpoints, especially those with unusually long cmdinput parameters, or monitor network traffic for POST requests to /goform/formexeCommand with oversized parameter valuesAffected if Log entries or network traffic show malformed requests to the formexeCommand endpoint - may indicate exploitation attempts
You are affected if you have a Tenda AC500 router running firmware version 2.0.1.9(1307) with the router's management interface accessible from an external network.
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 dataSince the vendor has not responded to this disclosure, apply compensating controls such as restricting network access to the router's management interface, implementing firewall rules to block external access to the /goform/* endpoints, or upgrading to a patched firmware version if available.
- Consultation3.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-3909 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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- Version or environment caveats, and links to real fixes
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