CVE Catalog

CVE-2026-73443

MediumCVSS 4.7
Published: Updated: Translated: NVD NIST

Summary

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.

Risk Assessment

This can result in a denial of service for hosts using the virtual gateway address, as traffic may not fail over to the backup router. Organizations relying on VRRP for gateway high availability may experience extended network unavailability.

Recommendation

Consider implementing anti-replay protections for VRRPv2, such as using VRRPv3 or additional authentication mechanisms, and monitor network segments for repeated VRRP advertisements. Also track vendor updates from Arista regarding this issue.

Other vulnerabilities in Arista EOS

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS