---
title: "CVE-2026-73459: Arista EOS - Denial of Service"
description: "Arista EOS with IS-IS configured contains a denial of service caused by injection of specially crafted IS-IS LSP PDU, letting unauthenticated attackers cause legitimate LSP purging and traffic loss, exploit requires ability to inject IS-IS LSP PDU."
url: https://panop.io/threat-heartbeat/CVE-2026-73459/
---

# CVE-2026-73459 Arista EOS - Denial of Service

Arista EOS with IS-IS configured contains a denial of service caused by injection of specially crafted IS-IS LSP PDU, letting unauthenticated attackers cause legitimate LSP purging and traffic loss, exploit requires ability to inject IS-IS LSP PDU.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.17% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-73459)

## 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:N/A:H

Published

16 September 2026

Updated

15 October 2026

Weakness

[CWE-354](https://cwe.mitre.org/data/definitions/354.html)

## Vendor fix

Update to the latest version with IS-IS LSP PDU handling 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-2026-73459](https://nvd.nist.gov/vuln/detail/CVE-2026-73459)
- [https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160](https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160)

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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

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