CVE-2026-73458: On affected platforms running Arista EOS with authenticated Bidirectional Forwarding Detection (BFD) sessions configured, a specially crafted packet can cause the BFD session(s) to go down. This may result in undesirable network changes because various rou
On affected platforms running Arista EOS with authenticated Bidirectional Forwarding Detection (BFD) sessions configured, a specially crafted packet can cause the BFD session(s) to go down. This may result in undesirable network changes because various routing protocols monitor status on BFD session(s).
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Arista EOS (BFD)to a version that resolves this vulnerability.Fixed in 4.33.9M - Upgrade
Upgrade
Arista EOS (BFD)to a version that resolves this vulnerability.Fixed in 4.34.8M - Upgrade
Upgrade
Arista EOS (BFD)to a version that resolves this vulnerability.Fixed in 4.35.6M - Upgrade
Upgrade
Arista EOS (BFD)to a version that resolves this vulnerability.Fixed in 4.36.2F - Compensating control
Plan for and validate potential undesirable network changes, since various routing protocols monitor the status of BFD session(s) and may react when BFD sessions go down during/around remediation.
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Affected platforms running Arista EOS are exposed when authenticated BFD sessions are configured. The issue is relevant where routing protocols monitor the status of those BFD sessions.
What does an attacker need to do to trigger the impact?
An attacker can trigger the issue by sending a specially crafted packet. The supplied vector indicates network-based exploitation with low attack complexity, no privileges, and no user interaction required.
What operational impact should network teams expect?
Authenticated BFD sessions can be forced down, which can cause undesirable network changes because routing protocols use BFD session status for monitoring.