CVE-2026-19655: On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthent

Published Sep 15, 2026

Updated

On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthenticated attacker connected to a client-facing VLAN(s) where the relay is configured can send a specially crafted packet that causes the DHCP Relay service to restart.

Affected Software

1 affected component

Arista Arista EOS

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade Arista EOS to a version that resolves this vulnerability.
Fixed in 4.33.10M
Upgrade
Upgrade Arista EOS to a version that resolves this vulnerability.
Fixed in 4.34.8M
Upgrade
Upgrade Arista EOS to a version that resolves this vulnerability.
Fixed in 4.35.6M

Event History

Sep 15, 2026

CVE Published

via MITRE·08:56 PM

Data Sourced

via MITRE·08:56 PM

RemedyDescriptionSeverityWeakness

Frequently Asked Questions

Which deployments are exposed?

Affected Arista EOS platforms are exposed when DHCP relay or snooping is configured with Option 82, or when the DHCP server uses match criteria based on Option 82. The attacker must be connected to a client-facing VLAN where the relay is configured.

What access does an attacker need?

The attacker does not need authentication or user interaction. They need network access to a relevant client-facing VLAN and must send a specially crafted packet.

What is the operational impact of successful exploitation?

Successful exploitation causes the DHCP Relay service to restart. The provided information does not describe any confidentiality or integrity impact.