CVE-2026-73443: Arista Networks Eos

Medium severity, CVSS 4.7. EPSS: 0.3% chance of exploitation in the next 30 days.

On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address.

Affected products

• Arista Networks Eos: from 4.36.0, up to and including 4.36.1F; from 4.35.0, up to and including 4.35.5M; from 4.34.0, up to and including 4.34.7M; from 4.33.0, up to and including 4.33.9M

Published 2026-09-16. Last modified 2026-09-17.