---
id: CVE-2026-73438
title: >-
  On affected platforms running Arista EOS with Open Shortest Path First version
  3 (OSPFv3) configured, an unauthenticated attacker on the same OSPFv3
  broadcast domain can send a specially crafted set of packets that can cause
  the Ospf3 ag…
summary: >-
  On affected platforms running Arista EOS with Open Shortest Path First version
  3 (OSPFv3) configured, an unauthenticated attacker on the same OSPFv3
  broadcast domain can send a specially crafted set of packets that can cause
  the Ospf3 ag…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-617
vendor: Arista Networks
product: EOS
affected:
  - EOS >= 4.36.0F <= 4.36.1F
  - EOS >= 4.35.0F <= 4.35.5M
  - EOS >= 4.34.0F <= 4.34.7M
  - EOS >= 4.33.0F <= 4.33.9M
  - EOS >= 1.0.0 < 4.33.0F
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:17:30.513'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73438'
references:
  - url: >-
      https://www.arista.com/en/support/advisories-notices/security-advisory/24728-security-advisory-0172
    label: psirt@arista.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T17:57:36.961511Z'
ingestedAt: '2026-09-16T09:53:11.602Z'
epss: 0.00246
epssPercentile: 0.14144
---

## Overview

On affected platforms running Arista EOS with Open Shortest Path First version 3 (OSPFv3) configured, an unauthenticated attacker on the same OSPFv3 broadcast domain can send a specially crafted set of packets that can cause the Ospf3 agent to restart unexpectedly. The crash results in the loss of all OSPFv3 adjacencies on the affected device and may disrupt routing across the broader OSPF domain until the agent recovers.

This issue was reported externally by Dravanet Inc., and Arista is not aware of any malicious exploitation of this vulnerability in customer networks.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.