CVE-2021-25849
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 · uneditedAn integer underflow was discovered in userdisk/vport_lldpd in Moxa Camera VPort 06EC-2V Series, version 1.1, improper validation of the PortID TLV leads to Denial of Service via a crafted lldp packet.
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 confidenceAn integer underflow vulnerability exists in the LLDP (Link Layer Discovery Protocol) implementation (userdisk/vport_lldpd) of Moxa Camera VPort 06EC-2V Series v1.1. The PortID TLV (Type-Length-Value) field is not properly validated before processing, allowing a specially crafted LLDP packet to trigger an integer underflow, leading to denial of service.
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<= 1.1<= 1.1<= 1.1<= 1.1<= 1.1<= 1.1<= 1.1<= 1.1CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 device modelAccess the camera web interface or use network discovery to confirm the device is a Moxa VPort 06EC-2V Series camera (06ec-2v26m, 06ec-2v36m, 06ec-2v42m variants)Affected if The device is a Moxa VPort 06EC-2V Series camera
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Check the firmware versionLocate the firmware version information in the camera web interface under System > Firmware/Software or similar, or use the manufacturer's management tool to query the deviceAffected if Firmware version is 1.1 or lower (the vulnerability exists in firmware <= 1.1)
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Confirm LLDP service is runningCheck if the LLDP service (vport_lldpd) is enabled on the camera - this can be done via the web interface network settings, or by querying the device via SNMP or the manufacturer's management APIAffected if LLDP is enabled and running on the device - the vulnerability only affects the LLDP implementation when it processes incoming LLDP packets
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Inspect LLDP configurationReview the LLDP settings in the camera's network configuration panel to determine if PortID TLV processing is active; LLDP must be enabled for the vulnerability to be exploitableAffected if LLDP is enabled with default or user-configured PortID TLV settings - the flaw is in how the PortID TLV field is validated before processing
You are affected if you have a Moxa VPort 06EC-2V Series camera (any variant) running firmware version 1.1 or lower with LLDP enabled, as the integer underflow occurs in the PortID TLV processing within the vport_lldpd component.
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 dataApply vendor firmware updates if available; otherwise, isolate affected devices on a restricted network segment and filter or disable LLDP traffic at network boundaries to prevent unauthenticated crafted packets from reaching vulnerable devices.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-25849 — 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-2021-25849 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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