2.6
LOW CVSS 3.1
CVE-2026-77191
All of the CVEs covered in this advisory apply to affected platforms running Arista EOS with 802.1X authentication and authorization enabled and Access Control Lists (ACLs) configured for per-supplicant policy enforcement. An authenticated supplicant on an
Description

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.

INFO

Published Date :

Sept. 14, 2026, 10:06 p.m.

Last Modified :

Sept. 14, 2026, 10:06 p.m.

Remotely Exploit :

No

Source :

Arista
Affected Products

The following products are affected by CVE-2026-77191 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Arista_networks eos
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 LOW c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7
CVSS 4.0 LOW c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7
Solution
Remediate by tightening authorization enforcement timing and validating access controls post-authentication.
  • Ensure ACLs are applied immediately after authentication.
  • Validate network access controls post-authentication.
  • Implement tighter authorization policies.
  • Review network device configuration.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-77191 vulnerability anywhere in the article.

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.