CVE-2026-77190: CWE-20 Improper Input Validation in Arista Networks EOS
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.
CVE-2026-77190: CWE-20 Improper Input Validation in Arista Networks EOS
Description
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.
CVSS v3.1
Score 6.5medium
Affected software
Arista Networks
EOS
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Arista
- Date Reserved
- 2026-08-20T16:41:21.387Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aaa6ccc55bf5e2cf558c5cf
Added to database: 09/16/2026, 10:17:48 UTC
Last updated: 09/16/2026, 10:17:48 UTC
Views: 1
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