---
id: CVE-2026-73458
title: >-
  On affected platforms running Arista EOS with authenticated Bidirectional
  Forwarding Detection (BFD) sessions configured, a specially crafted packet can
  cause the BFD session(s) to go down
summary: >-
  On affected platforms running Arista EOS with authenticated Bidirectional
  Forwarding Detection (BFD) sessions configured, a specially crafted packet can
  cause the BFD session(s) to go down. This may result in undesirable network
  changes …
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'
cwe:
  - CWE-303
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 <= 4.33.8M
published: '2026-09-15'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:08:50.420'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73458'
references:
  - url: >-
      https://www.arista.com/en/support/advisories-notices/security-advisory/24710-security-advisory-0154
    label: psirt@arista.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-15T19:38:30.537124Z'
ingestedAt: '2026-09-15T19:42:58.813Z'
epss: 0.00383
epssPercentile: 0.32277
---

## Overview

On affected platforms running Arista EOS with authenticated Bidirectional Forwarding Detection (BFD) sessions configured, a specially crafted packet can cause the BFD session(s) to go down. This may result in undesirable network changes because various routing protocols monitor status on BFD session(s).

## Remediation

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