---
id: CVE-2026-73435
title: >-
  On affected platforms running Arista EOS with Open Shortest Path First version
  2 (OSPFv2) configured, a specially crafted OSPFv2 packet from an
  unauthenticated attacker on the same broadcast segment, with OSPFv2
  authentication configured…
summary: >-
  On affected platforms running Arista EOS with Open Shortest Path First version
  2 (OSPFv2) configured, a specially crafted OSPFv2 packet from an
  unauthenticated attacker on the same broadcast segment, with OSPFv2
  authentication configured…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H'
cwe:
  - CWE-345
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: '2026-09-16T19:09:28.447'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73435'
references:
  - url: >-
      https://www.arista.com/en/support/advisories-notices/security-advisory/24727-security-advisory-0171
    label: psirt@arista.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T15:28:37.069647Z'
ingestedAt: '2026-09-16T09:53:11.606Z'
epss: 0.00188
epssPercentile: 0.07503
---

## Overview

On affected platforms running Arista EOS with Open Shortest Path First version 2 (OSPFv2) configured, a specially crafted OSPFv2 packet from an unauthenticated attacker on the same broadcast segment, with OSPFv2 authentication configured can cause adjacency flapping and packet loss. The disruption can affect routing across the broader OSPF domain.

## Remediation

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