Vulnerability · Published Sep 16, 2026 · Assigned by Arista

CVE-2026-73435Security Advisory 0171

High 8.2

In plain English

A high-severity insufficient verification of data authenticity in EOS from Arista Networks. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).

Severity (CVSS 3.1)8.2High

Exploit odds (30 days)0.2%top 91.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

On affected platforms running Arista EOS with Open Shortest Path First version 2 (OSPFv2) configured, a specially crafted OSPFv2 packet from an unauthenticated attacker on the same broadcast segment, with OSPFv2 authentication configured can cause adjacency flapping and packet loss. The disruption can affect routing across the broader OSPF domain.

Affected products (as reported)

Vendor	Product	Versions
Arista Networks	EOS	4.36.0F – through 4.36.1F4.35.0F – through 4.35.5M4.34.0F – through 4.34.7M4.33.0F – through 4.33.9M1.0.0 – before 4.33.0F

Weakness: CWE-345 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H

References

Security Advisory 0171 vendor-advisory