CVE-1999-0763
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 · uneditedNetBSD on a multi-homed host allows ARP packets on one network to modify ARP entries on another connected network.
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 confidenceNetBSD contains a vulnerability in its ARP handling on multi-homed hosts where ARP packets received on one network interface can incorrectly modify ARP cache entries for a different, separate network interface. This allows ARP poisoning on one network segment to affect ARP tables on another connected network segment.
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= 1.3CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:P/A:P
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 NetBSD operating systemRun 'uname -a' or check '/etc/release' to identify the operating systemAffected if The system is not running NetBSD (this CVE only affects NetBSD)
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Verify NetBSD version is 1.3Run 'uname -r' to get the release version, or check the contents of '/usr/src/sys/version' if availableAffected if The installed version is exactly NetBSD 1.3 (this specific version is affected)
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Check for multi-homed configurationRun 'ifconfig -a' to list all network interfaces. Identify if the system has multiple distinct network interfaces (such as eth0, eth1, or le0, le1) each connected to different network segmentsAffected if The system has two or more network interfaces on different IP subnets (the vulnerability only manifests on multi-homed hosts)
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Verify ARP is in useRun 'arp -a' to display the ARP cache table. If entries exist, ARP is active on the systemAffected if ARP cache contains entries - the vulnerability allows ARP poisoning on one interface to corrupt the cache for another interface
A user is affected if they are running NetBSD 1.3 with multiple network interfaces on different subnets, and ARP is being used on the system.
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 the appropriate NetBSD security patch or upgrade to a fixed version of NetBSD. For defense-in-depth, implement network segmentation or VLANs to limit the impact of ARP poisoning between network segments.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-1999-0763 — 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-1999-0763 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
- No weaponised exploit code, or anything meant to cause harm
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