---
id: CVE-2026-73443
title: >-
  On affected platforms running Arista EOS with VRRPv2 IP-AH authentication
  configured, an unauthenticated attacker within the same layer 2 network
  segment on which VRRP is running can capture a legitimate authenticated VRRP
  advertisement …
summary: >-
  On affected platforms running Arista EOS with VRRPv2 IP-AH authentication
  configured, an unauthenticated attacker within the same layer 2 network
  segment on which VRRP is running can capture a legitimate authenticated VRRP
  advertisement …
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L'
cwe:
  - CWE-294
vendor: Arista Networks
product: EOS
affected:
  - EOS >= 4.36.0 <= 4.36.1F
  - EOS >= 4.35.0 <= 4.35.5M
  - EOS >= 4.34.0 <= 4.34.7M
  - EOS >= 4.33.0 <= 4.33.9M
published: '2026-09-16'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T19:16:57.003'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73443'
references:
  - url: >-
      https://www.arista.com/en/support/advisories-notices/security-advisory/24713-security-advisory-0157
    label: psirt@arista.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-17T18:33:08.446292Z'
ingestedAt: '2026-09-16T19:02:30.725Z'
epss: 0.00273
epssPercentile: 0.19948
---

## Overview

On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address.

## Remediation

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