CVE-2026-2379: Arista EOS IPsec Tunnel Sequence Number Mismatch via Interface Flaps when Anti-Replay is Disabled

Published Jun 5, 2026

Updated

On affected platforms with hardware IPSec support running Arista EOS with certain IPsec features enabled, EOS may exhibit unexpected behavior in specific cases. Physical interface flaps and certain agent restarts can cause IPsec tunnel re-establishment with existing Security Associations, resulting in sequence number mismatches between tunnel endpoints potentially causing unstable communication.

Affected Software

1 affected component

Arista Arista EOS

Remediation

Information

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release that contains all the fixes listed below. For more information about upgrading see: EOS User Manual: Upgrades and Downgrades https://www.arista.com/en/um-eos/eos-upgrades-and-downgrades CVE-2026-2379 has been fixed in the following releases: * 4.35.0F and later releases in the 4.35.x train * 4.34.4M and later releases in the 4.34.x train * 4.33.6M and later releases in the 4.33.x train * 4.32.8M and later releases in the 4.32.x train * 4.31.10M and later releases in the 4.31.x train

Event History

Jun 5, 2026

CVE Published

via MITRE·05:59 PM

Data Sourced

via MITRE·05:59 PM

RemedyDescriptionSeverityWeakness

Data Sourced

via NVD·06:17 PM

DescriptionSeverityWeakness

Oct 20, 58397

Event

via NVD·09:57 PM

Frequently Asked Questions

What is the severity of CVE-2026-2379?

CVE-2026-2379 has a medium severity rating of 5.9.

How do I fix CVE-2026-2379?

To resolve CVE-2026-2379, upgrade to a remediated software version of Arista EOS.

What impact does CVE-2026-2379 have on my system?

CVE-2026-2379 may cause unexpected behavior in IPsec tunnels when certain conditions are met, particularly during interface flaps.

Is CVE-2026-2379 specific to any hardware?

Yes, CVE-2026-2379 affects platforms with hardware IPSec support running Arista EOS.

What should I do if I experience issues related to CVE-2026-2379?

If you encounter issues related to CVE-2026-2379, it is recommended to upgrade to the latest version of Arista EOS to avoid potential vulnerabilities.