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CVE-2026-73438: Security Advisory 0172
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-16 · updated 2026-09-16
- Weakness: CWE-617
Description
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.
Affected products
- Arista Networks EOS: from 4.36.0F through 4.36.1F; from 4.35.0F through 4.35.5M; from 4.34.0F through 4.34.7M; from 4.33.0F through 4.33.9M; from 1.0.0 before 4.33.0F — fixed in 4.33.0F
How to fix
Upgrade to a fixed version: Arista Networks EOS 4.33.0F. Check the vendor advisory for mitigations.
References
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