---
title: "CVE-2026-73435: Arista EOS - Denial of Service"
description: "Arista EOS with OSPFv2 configured contains a denial of service caused by specially crafted unauthenticated OSPFv2 packets, letting unauthenticated attackers cause adjacency flapping and packet loss, exploit requires attacker on same broadcast segment."
url: https://panop.io/threat-heartbeat/CVE-2026-73435/
---

# CVE-2026-73435 Arista EOS - Denial of Service

Arista EOS with OSPFv2 configured contains a denial of service caused by specially crafted unauthenticated OSPFv2 packets, letting unauthenticated attackers cause adjacency flapping and packet loss, exploit requires attacker on same broadcast segment.

CVSS base score 8.2 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.19% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-73435)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H

Published

16 September 2026

Updated

15 October 2026

Weakness

[CWE-345](https://cwe.mitre.org/data/definitions/345.html)

## Vendor fix

Update to the latest Arista EOS version with OSPFv2 fixes.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-73435](https://nvd.nist.gov/vuln/detail/CVE-2026-73435)
- [https://www.arista.com/en/support/advisories-notices/security-advisory/24727-security-advisory-0171](https://www.arista.com/en/support/advisories-notices/security-advisory/24727-security-advisory-0171)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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