CVE-2021-21960
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 stack-based buffer overflow vulnerability exists in both the LLMNR functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A specially-crafted network packet can lead to remote code execution. An attacker can send a malicious packet to trigger this vulnerability.
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 confidenceA stack-based buffer overflow vulnerability exists in the LLMNR (Link-Local Multicast Name Resolution) functionality of Sealevel Systems SeaConnect 370W wireless controller version 1.3.34. An attacker on the network can send a specially-crafted malicious packet to trigger the overflow and achieve remote code execution on the affected device.
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= 1.3.34CVSS 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
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 SeaConnect 370W firmware versionAccess the device administrative interface or API and locate the firmware version information, typically found under System Status, Device Info, or similar configuration sectionsAffected if The installed firmware version is exactly 1.3.34
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Confirm the device modelVerify that the affected device is specifically the SeaConnect 370W model, as other Sealevel products may have different version numberingAffected if The device model is SeaConnect 370W and firmware equals 1.3.34
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Locate LLMNR service configurationNavigate to the network or advanced settings menu in the device admin interface and look for LLMNR (Link-Local Multicast Name Resolution) settingsAffected if LLMNR functionality is present and enabled on the device
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Assess network exposureDetermine if the device is accessible on the network by untrusted actors, for example by checking if it is placed in a trusted network segment without firewall protectionsAffected if The device is reachable from untrusted network segments while LLMNR is enabled
The device is affected if it is a SeaConnect 370W running firmware version 1.3.34 with LLMNR functionality enabled and accessible to potential attackers on the 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 dataIf vendor-supplied firmware patches are unavailable, disable LLMNR functionality if not required, implement network segmentation to limit exposure, and consider replacing the device if it has reached end-of-life.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21960 — 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-2021-21960 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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