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Nx OsOperating system · Cisco

CVE-2018-0395

MEDIUM · 5.3 CVSS v3.0 Published 2018-10-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
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 Link Layer Discovery Protocol (LLDP) implementation for Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition when the device unexpectedly reloads. The vulnerability is due to improper input validation of certain type, length, value (TLV) fields of the LLDP frame header. An attacker could exploit this vulnerability by sending a crafted LLDP packet to an interface on the targeted device. A successful exploit could allow the attacker to cause the switch to reload unexpectedly.

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 Link Layer Discovery Protocol (LLDP) implementation for Cisco FXOS and NX-OS software allows an unauthenticated, adjacent attacker to cause a denial of service condition. The issue stems from improper input validation of Type, Length, Value (TLV) fields in the LLDP frame header. An attacker sending a crafted LLDP packet to an affected interface can trigger an unexpected device reload.

MitigationApply the vendor-supplied software update/patch for Cisco FXOS and NX-OS when available. As an interim mitigation, consider disabling LLDP on interfaces where it is not required or implementing network access controls to restrict LLDP packet sources to trusted 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:= 6.0\(4\)= 6.1\(3\)s2= r231= 12.3\(1e\)= 3.2\(3d\)c
Firepower Extensible Operating SystemOperating system
Affected:= r231

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

CVSS:3.0/AV:A/AC:H/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 installed NX-OS or FXOS version
    Run 'show version' on the Cisco device CLI to obtain the software version number
    Affected if The version matches one of the affected releases: 6.0(4), 6.1(3)s2, r231, 12.3(1e), or 3.2(3d)c for NX-OS; or r231 for FXOS
  2. Determine if LLDP is globally enabled
    Run 'show lldp global' or 'show lldp' command to check the LLDP global configuration status
    Affected if LLDP is enabled (output shows 'LLDP is enabled' or similar)
  3. Check which interfaces have LLDP enabled
    Run 'show lldp interface' or 'show lldp interface detail' to list interfaces with LLDP transmit and receive enabled
    Affected if One or more interfaces show LLDP as enabled (Tx and/or Rx)
  4. Verify LLDP is running on active data interfaces
    Review the output from 'show ldp interface' or 'show lldp interface' focusing on interfaces in use (not management-only)
    Affected if LLDP is enabled on any operational interface, especially access or trunk ports

A device is affected if it runs a vulnerable NX-OS or FXOS version AND has LLDP enabled on any interface, making it susceptible to denial of service from crafted LLDP packets.

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 vendor-supplied software update/patch for Cisco FXOS and NX-OS when available. As an interim mitigation, consider disabling LLDP on interfaces where it is not required or implementing network access controls to restrict LLDP packet sources to trusted devices.

Fix this in Nx Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,300
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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-2018-0395 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