Arista EOS up to 4.36.2F BFD denial of service

Summaryinfo

A vulnerability was found in Arista EOS up to 4.36.2F. It has been declared as critical. Affected by this issue is some unknown functionality of the component BFD. The manipulation results in denial of service. This vulnerability is reported as CVE-2026-121368. The attack can be launched remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Arista EOS up to 4.36.2F. Affected is some unknown processing of the component BFD. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

On affected platforms running Arista EOS with Bidirectional Forwarding Detection (BFD) configured to use keyed MD5 or keyed SHA1 authentication, an unauthenticated attacker with network adjacency (direct or multi-hop) to a BFD-enabled interface can send a specially crafted BFD packet resulting in a system reboot.

The advisory is available at arista.com. This vulnerability is traded as CVE-2026-121368 since 11/03/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 4.32.0F or 4.33.0F eliminates this vulnerability.

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Productinfo

Vendor

• Arista

Name

• EOS

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 4.15
• 4.16
• 4.17
• 4.18
• 4.19
• 4.20
• 4.21
• 4.22
• 4.23
• 4.24
• 4.25
• 4.26
• 4.27
• 4.28
• 4.29
• 4.30
• 4.31
• 4.32
• 4.33.10M
• 4.34.8M
• 4.35.6M
• 4.36.2F

License

• commercial

CPE 2.3info

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• 🔒
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CPE 2.2info

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• 🔒
• 🔒

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