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Nx OsOperating system · Cisco

CVE-2013-6683

MEDIUM · 6.1 CVSS v2.0 Published 2013-11-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
66/100
Remediation priority · Elevated
No privileges Zero-click

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 · unedited
The IPv6 implementation in Cisco NX-OS does not properly handle neighbor-table adjacencies, which allows remote attackers to cause a denial of service (NS processing outage) via a series of malformed packets, aka Bug ID CSCtd15904.

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 confidence

This vulnerability exists in the IPv6 neighbor discovery implementation of Cisco NX-OS. The neighbor-table adjacency handling flaw allows remote attackers to send malformed packets that cause a processing outage for Neighbor Solicitation (NS) messages, resulting in a denial of service condition.

MitigationApply the Cisco NX-OS patch or upgrade to a fixed version as provided through Cisco's official bug fix (CSCtd15904). Prior to patching, consider network-based filtering of malformed IPv6 packets at perimeter devices.

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
Nx OsOperating system
Affected:all versions

CVSS 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
Adjacent
Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete

AV:A/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 checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Cisco NX-OS is running
    Run 'show version' and look for 'NX-OS' in the software identification output
    Affected if The device runs Cisco NX-OS software (all versions are affected)
  2. Check if IPv6 feature is enabled
    Run 'show feature | include ipv6' to verify the IPv6 feature status
    Affected if The IPv6 feature is enabled on the NX-OS device
  3. Verify IPv6 interfaces are configured
    Run 'show ipv6 interface' to list interfaces with IPv6 addresses
    Affected if Any interface has an IPv6 address assigned and is operational
  4. Confirm IPv6 neighbor discovery is active
    Run 'show ipv6 neighbors' to inspect the neighbor cache
    Affected if The device is actively processing IPv6 neighbor entries via Neighbor Solicitation messages

Any Cisco NX-OS device with IPv6 enabled and actively processing Neighbor Solicitation messages is vulnerable to this DoS flaw.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco NX-OS patch or upgrade to a fixed version as provided through Cisco's official bug fix (CSCtd15904). Prior to patching, consider network-based filtering of malformed IPv6 packets at perimeter devices.

Fix this in Nx Os Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2013-6683 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data