CVE-2026-73435

Security Advisory 0171

Published Sep 16, 2026 CVSS 4.0 · 7 High EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Solution

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release that contains all the fixes listed below. CVE-2026-73435 has been fixed in the following releases: - 4.36.2F and later releases in the 4.36.x train - 4.35.6M and later releases in the 4.35.x train - 4.34.7.1M and later releases in the 4.34.x train - 4.33.10M and later releases in the 4.33.x train A hotfix is available for the following releases: 4.36.1F, 4.35.5M, 4.34.7M, 4.33.9M. URL: https://www.arista.com/support/advisories-notices/sa-download/?sa171-SecurityAdvisory171_CVE-2026-73435.swix SWIX hash (SHA512): 4c4ff053d8165f347b45dfcafc2d20396e3eb00869b0088f3128be7f53b2a028b479fa8279849c800b5916ab9aaf8077718a68e3bf4277d55b44076650de0aa7 Note: Installing/uninstalling the SWIX will cause the Ospf process to restart.


Vendor Workaround

No mitigation is available for CVE-2026-73435.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Arista
Arista eos
Vendors & Products Arista
Arista eos
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Security Advisory 0171
Weaknesses CWE-345
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H'}

cvssV4_0

{'score': 7, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Arista
Published
Updated
Sep 16, 2026, 3:29 PM
Reserved
Aug 12, 2026, 4:39 PM
Status
Awaiting Analysis
Published
Sep 16, 2026, 10:16 AM
Modified
Sep 16, 2026, 7:09 PM