CVE-2026-77190: Arista Networks Eos

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

On affected platforms running Arista EOS, an unauthenticated attacker who is network-adjacent to the switch and able to connect to a device with PIM Sparse Mode and MLAG configured, can send malformed messages that cause the Pimsm agent to terminate unexpectedly. The Pimsm agent is automatically restarted, but repeated attacks can cause the agent to restart continuously, resulting in a sustained denial of service.

Affected products

• Arista Networks Eos: from 4.36.0F, up to and including 4.36.1F; from 4.35.0F, up to and including 4.35.5M; from 4.34.2F, up to and including 4.34.7M

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