High severity · published Sep 16, 2026
CVE-2026-73435
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,
8.2
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 8% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EO
EOS · Arista Networks
4.36.0F through 4.36.1F; 4.35.0F through 4.35.5M; 4.34.0F through 4.34.7M; 4.33.0F through 4.33.9M; 1.0.0 before 4.33.0F · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-73435
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-73435
www.arista.com
https://www.arista.com/en/support/advisories-notices/security-advisory/24727-security-advisory-0171
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