---
id: CVE-2026-77191
title: >-
  An authenticated supplicant on an adjacent network may bypass intended network
  authorization policy and send unrestricted traffic during a brief window
  (milliseconds to seconds) between the completion of the authentication phase
  and the …
summary: >-
  An authenticated supplicant on an adjacent network may bypass intended network
  authorization policy and send unrestricted traffic during a brief window
  (milliseconds to seconds) between the completion of the authentication phase
  and the …
severity: low
cvss: 2.6
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-862
vendor: Arista Networks
product: EOS
affected:
  - EOS >= 4.35.0 <= 4.35.0.3F
  - EOS >= 4.34.0 <= 4.34.5M
  - EOS >= 0.0.0 <= 4.33.7.1M
published: '2026-09-14'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:36:52.890'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77191'
references:
  - url: >-
      https://www.arista.com/en/support/advisories-notices/security-advisory/24706-security-advisory-0150
    label: psirt@arista.com
tags:
  - nvd
  - cve.org
epss: 0.0014
epssPercentile: 0.03729
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-15T13:40:55.120355Z'
ingestedAt: '2026-09-14T23:17:06.519Z'
---

## Overview

An authenticated supplicant on an adjacent network may bypass intended network authorization policy and send unrestricted traffic during a brief window (milliseconds to seconds) between the completion of the authentication phase and the full enforcement of its assigned ACL.

## Remediation

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