On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address.
CVSS Details
- CVSS 4.0 Base Score: 5.3 (MEDIUM)
- CVSS 4.0 Vector: (CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 4.7
- CVSS 3.1 Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Arista Eos | — | Upgrade to a remediated software version: 4.36.2F and above releases in the 4.36.x train, 4.35.6M and above releases in the 4.35.x train, 4.34.8M and above releases in the 4.34.x train, or 4.33.10M and above releases in the 4.33.x train. After upgrading, enable replay protection with the global configuration command: vrrp ipv4 authentication anti-replay | Sep 10, 2026 | Sep 9, 2026 |
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