---
id: CVE-2026-73446
title: >-
  On affected platforms running Arista EOS with IS-IS configured on a broadcast
  interface, an unauthenticated attacker can send a crafted IS-IS Hello Protocol
  Data Unit (PDU) that causes the device to tear down an established IS-IS
  adjacen…
summary: >-
  On affected platforms running Arista EOS with IS-IS configured on a broadcast
  interface, an unauthenticated attacker can send a crafted IS-IS Hello Protocol
  Data Unit (PDU) that causes the device to tear down an established IS-IS
  adjacen…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'
cwe:
  - CWE-696
vendor: Arista Networks
product: EOS
affected:
  - EOS >= 4.36.0 <= 4.36.1F
  - EOS >= 4.35.0 <= 4.35.5M
  - EOS >= 4.34.0 <= 4.34.7.1M
  - EOS >= 4.33.0 <= 4.33.9M
  - EOS >= 4.32.0 < 4.33.0F
  - EOS >= 4.31.0 < 4.32.0F
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:17:26.997'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73446'
references:
  - url: >-
      https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160
    label: psirt@arista.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T19:34:09.117613Z'
ingestedAt: '2026-09-15T23:46:25.574Z'
epss: 0.00247
epssPercentile: 0.1634
---

## Overview

On affected platforms running Arista EOS with IS-IS configured on a broadcast interface, an unauthenticated attacker can send a crafted IS-IS Hello Protocol Data Unit (PDU) that causes the device to tear down an established IS-IS adjacency. This may result in traffic disruption and loss of IP reachability for prefixes advertised through that adjacency.

## Remediation

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