CVE-2026-11503
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 security vulnerability has been detected in Tenda CX12L 16.03.53.12. The affected element is the function form_fast_setting_wifi_set of the file /goform/fast_setting_wifi_set of the component Wi-Fi Configuration Endpoint. Such manipulation of the argument ssid leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed publicly and may be used.
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 confidenceStack-based buffer overflow in Tenda CX12L router firmware 16.03.53.12 within the Wi-Fi configuration endpoint /goform/fast_setting_wifi_set. The ssid parameter passed to function form_fast_setting_wifi_set lacks proper bounds checking, allowing an attacker to overflow a stack buffer by providing an oversized SSID value. This can enable remote code execution given the public availability of exploit code and CVSS 8.8 rating.
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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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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Confirm router model is Tenda CX12LInspect the router device label or access the web management interface and look for the model number in the status or administration pageAffected if The device is not a Tenda CX12L router (different models are not affected by this specific CVE)
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Identify installed firmware versionLog into the router web interface, navigate to Administration or System settings, and locate the firmware version displayed. Alternatively, check via telnet/SSH if those services are enabledAffected if Firmware version is exactly 16.03.53.12 (this is the only version explicitly listed as affected in the CVE summary)
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Verify web management interface is accessibleAttempt to reach the router IP address from the network where the router is deployed. Check if http://[routerIP] returns a login pageAffected if The web interface is not accessible at all (the vulnerability cannot be exploited if the interface is unreachable)
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Determine if remote WAN access is enabledLog into the router web interface, go to Advanced or Administration settings, and check for 'Remote Management', 'WAN Access', or 'Remote Administration' options. Confirm whether remote access from outside the local network is permittedAffected if Remote WAN access to the web interface is enabled (this increases exposure to remote exploitation of the vulnerable endpoint)
A user is affected if they have a Tenda CX12L router running firmware version 16.03.53.12 with the web management interface accessible (especially if remote WAN access is enabled), as this allows reachability to the vulnerable /goform/fast_setting_wifi_set endpoint.
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 dataIf vendor firmware update unavailable, disable remote administration or place device behind a restrictive firewall; the fix requires adding length validation and safe string handling for the ssid parameter in the vulnerable function.
- 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-2026-11503 — 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-2026-11503 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
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