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EosOperating system · Arista

CVE-2018-14008

MEDIUM · 6.5 CVSS v3.0 Published 2019-08-15
Fix available
A fix is available. Upgrade to after 4.21.0f 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
Arista EOS through 4.21.0F allows a crash because 802.1x authentication is mishandled.

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 · moderate confidence

Arista EOS through version 4.21.0F contains a vulnerability in 802.1x authentication handling that causes the device to crash, resulting in a denial of service condition.

MitigationUpgrade Arista EOS to a version beyond 4.21.0F that contains the fix; if 802.1x is not required, consider disabling it as a temporary mitigation until the upgrade can be performed.

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
EosOperating system
Affected:<= 4.21.0f

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:3.0/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. Check Arista EOS version
    Execute 'show version' on the device CLI and locate the 'Software image version' or 'EOS version' field
    Affected if The displayed version string is 4.21.0F or lower (e.g., 4.21.0, 4.20.x, 4.19.x, etc.)
  2. Confirm 802.1x is enabled
    Execute 'show dot1x' or 'show running-config | include dot1x' to check if 802.1x authentication is configured and active on any interface
    Affected if The output shows 802.1x is enabled or configured on one or more interfaces (the vulnerability requires 802.1x to be active)
  3. Verify 802.1x status on specific interfaces
    Execute 'show dot1x interface' to see which interfaces have 802.1x authentication enabled
    Affected if Any interface shows 'Enabled' or 'Operational' status for 802.1x - this indicates the vulnerable feature is in use
  4. Check for crash logs related to 802.1x
    Execute 'show logging' and search for recent crash logs, core dumps, or 802.1x related errors using '| include dot1x|crash|exception'
    Affected if Recent crash events tied to 802.1x processing are found in logs

A system is affected if it runs Arista EOS version 4.21.0F or lower AND has 802.1x authentication enabled on any interface, as the vulnerability requires both conditions to trigger the denial of service.

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 a release after 4.21.0f
Interim mitigation

Upgrade Arista EOS to a version beyond 4.21.0F that contains the fix; if 802.1x is not required, consider disabling it as a temporary mitigation until the upgrade can be performed.

Fix this in Eos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2018-14008 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