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Arista NetworksCVE-2026-73438

Arista Networks EOS: reachable assertion

High7.0CVE-2026-73438 · Published Sep 16, 2026

On affected platforms running Arista EOS with Open Shortest Path First version 3 (OSPFv3) configured, an unauthenticated attacker on the same OSPFv3 broadcast domain can send a specially crafted set of packets that can cause the Ospf3 agent to restart unexpectedly. The crash results in the loss of all OSPFv3 adjacencies on the affected device and may disrupt routing across the broader OSPF domain until the agent recovers. This issue was reported externally by Dravanet Inc., and Arista is not aware of any malicious exploitation of this vulnerability in customer networks.

Arista Networks advisory

Affected versions

PackageAffectedFixed in
EOS
Product
>= 4.36.0F, <= 4.36.1FNo fix yet
>= 4.35.0F, <= 4.35.5MNo fix yet
>= 4.34.0F, <= 4.34.7MNo fix yet
>= 4.33.0F, <= 4.33.9MNo fix yet
Details and references
CVSS 4.0
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity from
the vendor (its own CVE record or advisory)
Weakness
CWE-617

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