CVE-2018-5254
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 · uneditedArista EOS before 4.20.2F allows remote BGP peers to cause a denial of service (Rib agent restart) via a malformed path attribute in an UPDATE message.
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 confidenceArista EOS before version 4.20.2F contains a vulnerability in the BGP (Border Gateway Protocol) implementation where processing a malformed path attribute in a BGP UPDATE message causes the Rib (Routing Information Base) agent to crash and restart, resulting in denial of service. The vulnerability is triggered by remote BGP peers sending specifically crafted UPDATE messages.
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< 4.20.2fCVSS 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/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 checksWork through these to decide whether this CVE applies to you.
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Determine the installed Arista EOS versionRun the command 'show version' on the switch CLI and locate the EOS software version string (typically displayed as something like '4.20.xF')Affected if The version number is lower than 4.20.2F (for example, 4.19.5F, 4.18.0F, etc.)
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Verify BGP is enabled on the deviceRun 'show ip bgp summary' or 'show running-config | include bgp' to confirm BGP routing process is configured and activeAffected if BGP is configured and running on the device (the vulnerability only affects systems with BGP enabled)
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Confirm the device has BGP peersRun 'show ip bgp summary' and check for established peer connections under the 'State/PfxRcd' columnAffected if The device has active BGP peer relationships (the attack is triggered by malformed UPDATE messages from remote peers)
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Check the Rib agent statusRun 'show rib process' or 'show process' to verify the Rib (Routing Information Base) agent is runningAffected if The Rib agent is running (this is the component that crashes when malformed BGP UPDATE messages are received)
A system is affected if it runs Arista EOS version below 4.20.2F AND has BGP enabled with active peer relationships, making it vulnerable to a denial of service from crafted BGP UPDATE messages.
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 data4.20.2f
Upgrade Arista EOS to version 4.20.2F or later. As an interim control, restrict BGP peer relationships to trusted sources only and implement BGP message validation at border routers.
- Consultation3.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2018-5254 — 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-2018-5254 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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