CVE-2026-75944

Network service interruption via stale ACL reuse

Published Sep 14, 2026 · Updated Sep 14, 2026

Race condition in Arista EOS 4.36.1F allows remote authenticated users on adjacent networks to interrupt access via stale supplicant ACL reuse. During 802.1X re-authentication at hardware ACL capacity, AclAgent fails to remove a stale per-supplicant ACL and reapplies it to a new supplicant after restarting. Exposure requires authenticator-mode 802.1X with ACL-based RADIUS authorization, hardware ACL exhaustion, and an administrator-triggered AclAgent restart; the reported impact is network service interruption, not data disclosure or modification.

CVSS severity4.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Arista EOS 4.36.1F allows remote authenticated users on adjacent networks to interrupt access via stale supplicant ACL reuse. During 802.1X re-authentication at hardware ACL capacity, AclAgent fails to remove a stale per-supplicant ACL and reapplies it to a new supplicant after restarting. Exposure requires authenticator-mode 802.1X with ACL-based RADIUS authorization, hardware ACL exhaustion, and an administrator-triggered AclAgent restart; the reported impact is network service interruption, not data disclosure or modification.

The record

CVE
CVE-2026-75944
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
Arista Networks
Product
Arista EOS
Classifications
CWE-459
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.36.0 <=4.36.1F

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Arista Networks · Arista EOSversion=4.36.0 <=4.36.1F

Published CVSS scores

5.6Arista NetworksCVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
4.5Arista NetworksCVSS:3.1/AV:A/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-459Incomplete Cleanup

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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