CVE-2026-73453

Arista EOS contains a flaw (CWE-94) that lets an unauthenticated P4Runtime client achieve arbitrary code execution on switches configured with P4Runtime under certain conditions. It is triggered by sending a specially crafted packet during the initiation of a P4Runtime session, with no credentials or user interaction required. A successful attacker obtains complete administrative control over the compromised switch. Only deployments where P4Runtime is enabled are exposed; the feature is disabled by default in Arista EOS. The issue was found internally by Arista, and no public proof-of-concept or malicious exploitation in customer networks is known.

What to do: Upgrade to the fixed EOS release when Arista publishes it in the official advisory (fixed versions are not stated in the available data). If P4Runtime is not required, keep it disabled or disable it until patched; where it is required, restrict access to the P4Runtime service using control-plane and management-interface ACLs to trusted controllers only. Review switch configs for 'p4runtime' enablement and monitor Arista's advisory for updates.