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Nx OsOperating system · Cisco

CVE-2018-0331

MEDIUM · 6.5 CVSS v3.1 Published 2018-06-21
Fix available
A fix is available. Upgrade to 2.0.1.152 / 2.0.1.153 or later.
See remediation →
70/100
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
A vulnerability in the Cisco Discovery Protocol (formerly known as CDP) subsystem of devices running, or based on, Cisco NX-OS Software contain a vulnerability that could allow an unauthenticated, adjacent attacker to create a denial of service (DoS) condition. The vulnerability is due to a failure to properly validate certain fields within a Cisco Discovery Protocol message prior to processing it. An attacker with the ability to submit a Cisco Discovery Protocol message designed to trigger the issue could cause a DoS condition on an affected device while the device restarts. This vulnerability affects Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 3600 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvc89242, CSCve40943, CSCve40953, CSCve40965, CSCve40970, CSCve40978, CSCve40992, CSCve41000, CSCve41007.

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

A vulnerability in the Cisco Discovery Protocol (CDP) subsystem of NX-OS-based devices fails to properly validate certain fields within CDP messages prior to processing. An unauthenticated, adjacent attacker with network access to the same broadcast domain can send a specially crafted CDP packet that triggers a DoS condition, causing the affected device to restart.

MitigationApply the relevant Cisco software updates for the affected NX-OS versions. As an immediate workaround, disable CDP on vulnerable interfaces or implement network access control to restrict CDP traffic to trusted ports.

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:>= 7.1, < 7.1\(5\)n1\(1\)>= 7.3, < 7.3\(3\)n1\(1\)= 6.0= 7.0= 7.2>= 6.2, < 6.2\(20\)>= 7.2, < 7.2\(2\)d1\(3\)>= 7.3, < 7.3\(2\)d1\(1\)>= 8.1, < 8.1\(2\)>= 8.2, < 8.2\(1\)= 8.0< 7.0\(3\)i3
Firepower Extensible Operating SystemOperating system
Affected:>= 1.1, < 2.0.1.153>= 2.1.1, < 2.1.1.86>= 2.2.1, < 2.2.1.70
FxosOperating system
Affected:>= 2.2.2, < 2.2.2.14>= 1.1, < 2.0.1.152

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
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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 checks

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

  1. Identify the NX-OS version
    Run 'show version' on the device CLI to obtain the installed NX-OS software version
    Affected if The version falls within any of these ranges: >= 7.1 < 7.1(5)n1(1), >= 7.3 < 7.3(3)n1(1), = 6.0, = 7.0, = 7.2, >= 6.2 < 6.2(20), >= 7.2 < 7.2(2)d1(3), >= 7.3 < 7.3(2)d1(1), >= 8.1 < 8.1(2), >= 8.2 < 8.2(1), = 8.0, < 7.0(3)i3
  2. Identify the Firepower Extensible Operating System version
    Run 'show version' on the Firepower device to obtain the installed software version
    Affected if The version falls within: >= 1.1 < 2.0.1.153, >= 2.1.1 < 2.1.1.86, or >= 2.2.1 < 2.2.1.70
  3. Identify the FXOS version
    Run 'show version' on the FXOS device to obtain the installed software version
    Affected if The version falls within: >= 2.2.2 < 2.2.2.14 or >= 1.1 < 2.0.1.152
  4. Check if CDP is enabled globally
    Run 'show cdp global' in the NX-OS CLI to see if Cisco Discovery Protocol is enabled
    Affected if CDP is enabled (global CDP must be disabled for the device to not be vulnerable)
  5. Check if CDP is enabled per interface
    Run 'show cdp interface' to list interfaces with CDP actively running
    Affected if Any interface has CDP enabled, meaning the device can receive and process CDP packets

The device is affected if it runs a vulnerable NX-OS, Firepower Extensible OS, or FXOS version AND has CDP enabled on any interface.

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
Upgrade available Upgrade to 2.0.1.152 / 2.0.1.153 / 2.1.1.86 or later
Fixed in 2.0.1.1522.0.1.1532.1.1.86
Interim mitigation

Apply the relevant Cisco software updates for the affected NX-OS versions. As an immediate workaround, disable CDP on vulnerable interfaces or implement network access control to restrict CDP traffic to trusted ports.

Fix this in Nx Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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Scan for this in your stack

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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-2018-0331 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