CVE-2026-73438

MEDIUMCVSS 5.3/10EPSS 0.21%

Last modified

CVE-2026-73438 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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.. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Arista NetworksEOS>= 4.36.0F, <= 4.36.1F; >= 4.35.0F, <= 4.35.5M; >= 4.34.0F, <= 4.34.7M; >= 4.33.0F, <= 4.33.9M; >= 1.0.0, < 4.33.0F

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-73438?
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.
How severe is CVE-2026-73438?
CVE-2026-73438 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-73438?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST