CVE-2026-73449: On affected platforms running Arista EOS with both 802.1X port authentication and the RADIUS proxy feature configured with dynamic authorization, a low-privileged attacker on an adjacent network segment who induces a RADIUS packet through a configured RADI
On affected platforms running Arista EOS with both 802.1X port authentication and the RADIUS proxy feature configured with dynamic authorization, a low-privileged attacker on an adjacent network segment who induces a RADIUS packet through a configured RADIUS proxy client can prevent RADIUS dynamic authorization messages, including Change-of-Authorization (CoA) and Disconnect-Requests as defined in RFC 5176, from being applied to locally authenticated 802.1X sessions. This allows an endpoint session that a RADIUS server or network access control system has ordered disconnected to remain authorized on the network. Both 802.1X port authentication with dynamic authorization and RADIUS proxy with dynamic authorization must be explicitly configured for a deployment to be exposed to this issue. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Arista EOSto a version that resolves this vulnerability.Fixed in 4.34.8M - Upgrade
Upgrade
Arista EOSto a version that resolves this vulnerability.Fixed in 4.35.6M - Upgrade
Upgrade
Arista EOSto a version that resolves this vulnerability.Fixed in 4.36.2F - Configuration
The issue applies only when both 802.1X port authentication with dynamic authorization AND RADIUS proxy with dynamic authorization are explicitly configured; ensure this combined configuration is removed/avoided unless required, and still upgrade to a remediated EOS version at the earliest convenience.
Arista EOS 802.1X port authentication (dynamic authorization) and RADIUS proxy (dynamic authorization) dynamic authorization exposure condition = Ensure either 802.1X port authentication with dynamic authorization is not exposed or RADIUS proxy with dynamic authorization is not configured for the affected deployment
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Exposure requires both 802.1X port authentication with dynamic authorization and the RADIUS proxy feature with dynamic authorization to be explicitly configured. Deployments without this combination are not described as affected.
What access does an attacker need?
The attacker must be low privileged, located on an adjacent network segment, and able to induce a RADIUS packet through a configured RADIUS proxy client. No user interaction is required.
What is the operational impact of successful exploitation?
RADIUS dynamic authorization messages, including CoA and Disconnect-Requests, may not be applied to locally authenticated 802.1X sessions. An endpoint that the RADIUS server or NAC system has instructed to disconnect can remain authorized on the network.
Is there evidence of exploitation in customer environments?
Arista states that it is not aware of malicious exploitation of this vulnerability in customer networks.