CVE-2023-51736
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 · uneditedThis vulnerability exist in Skyworth Router CM5100, version 4.1.1.24, due to insufficient validation of user supplied input for the L2TP/PPTP Username parameter at its web interface. A remote attacker could exploit this vulnerability by supplying specially crafted input to the parameter at the web interface of the vulnerable targeted system. Successful exploitation of this vulnerability could allow the attacker to perform stored XSS attacks on the targeted system.
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 stored XSS vulnerability exists in the Skyworth Router CM5100 (v4.1.1.24) web interface where the L2TP/PPTP Username parameter fails to properly validate user-supplied input. An authenticated remote attacker can inject malicious JavaScript code through this parameter, which then executes when other users access the affected interface.
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= 4.1.1.24CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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 firmware versionAccess the router web administration interface and navigate to System Settings or Administration > Firmware Version. Alternatively, check the device label or use the router's status page to confirm the installed firmware version.Affected if The firmware version is exactly 4.1.1.24 (Skyworthdigital CM5100)
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Verify L2TP/PPTP configuration accessLog into the web interface and locate the L2TP or PPTP settings section, typically found under Network Settings, WAN settings, or VPN configuration menus.Affected if The L2TP/PPTP configuration interface is accessible and functional in the web interface
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Inspect the Username parameter fieldNavigate to the L2TP/PPTP username input field and examine its current value. Look for any unexpected characters, scripts, or encoded content that may indicate injection.Affected if The Username field contains JavaScript tags, event handlers, or suspicious encoded characters that were not personally entered by the current user
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Check for stored XSS payloadsView the L2TP/PPTP configuration page in multiple browser contexts (different browsers or incognito mode) to see if injected scripts execute automatically when the page loads.Affected if JavaScript code executes or the browser console shows XSS-related errors when viewing the L2TP/PPTP settings page
You are affected if the device is a Skyworth CM5100 running firmware version 4.1.1.24 and the L2TP/PPTP Username field contains any unexpected or malicious script content that executes when viewing the configuration page.
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 dataImplement strict input validation and output encoding for the L2TP/PPTP Username parameter. Until an official firmware patch is released, limit administrative web interface access to trusted users only and monitor for anomalous requests.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-51736 — 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-2023-51736 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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