iOSOperating system · Cisco
CVE-2012-3079
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 · uneditedCisco IOS 12.2 allows remote attackers to cause a denial of service (CPU consumption) by establishing many IPv6 neighbors, aka Bug ID CSCtn78957.
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 confidenceCisco IOS 12.2 contains a vulnerability in IPv6 neighbor discovery processing where an attacker can cause excessive CPU consumption by establishing a large number of IPv6 neighbor entries. This is a resource exhaustion vulnerability where the IPv6 neighbor table can be flooded, 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
iOSOperating system
= 12.2CVSS 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
- None
- Availability
- Complete
AV:N/AC:L/Au:N/C:N/I:N/A:C
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 Cisco IOS versionUse the command 'show version' to display the running IOS version. Look for version 12.2 in the output.Affected if The device runs Cisco IOS version 12.2 exactly (version string contains 12.2)
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Verify IPv6 is enabled on the deviceUse the command 'show ipv6 interface brief' to check if any interfaces have IPv6 configured. If IPv6 is not enabled, the device has no attack surface for this vulnerability.Affected if IPv6 is enabled and interfaces have IPv6 addresses assigned
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Inspect the IPv6 neighbor table sizeUse the command 'show ipv6 neighbor' to display all IPv6 neighbor entries. Count the total number of entries and note if it is unusually large.Affected if The neighbor table contains an abnormally large number of entries (hundreds to thousands) indicating a potential flood condition
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Monitor CPU utilization during IPv6 trafficUse the command 'show process cpu sorted' to observe CPU usage. Correlate this with periods of active IPv6 neighbor discovery traffic using 'show ipv6 traffic'.Affected if CPU utilization spikes to high levels when IPv6 neighbor discovery traffic is present or sustained
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Check for IPv6 neighbor discovery traffic patternsUse the command 'show ipv6 traffic' to examine neighbor discovery packet counters. Look for rapid increases in Neighbor Solicitation or Advertisement counts.Affected if There is a high rate or sustained burst of incoming IPv6 neighbor discovery packets
The device is affected if it runs Cisco IOS 12.2 with IPv6 enabled and is receiving or susceptible to IPv6 neighbor discovery traffic floods that cause excessive CPU consumption.
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 Cisco IOS security update for this vulnerability when available. In the interim, implement IPv6 traffic filtering or rate limiting on perimeter devices to restrict the rate of incoming IPv6 neighbor solicitation/advertisement messages.
Fix this in iOS
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 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 $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-3079 — 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-2012-3079 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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