CVE-2026-2379

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

State: Published
Severity: 8.2 High
Published: Jun 5, 2026
Updated: Jun 9, 2026
Reserved: Feb 11, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	8.2 High	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N	Arista
3.1	5.9 Medium	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N	Arista

Weaknesses

CWE-672 Operation on a Resource after Expiration or Release

Affected Products

Product	Versions
EOSArista Networks	4.34.0 through 4.34.3MAffected 4.33.0M through 4.33.5MAffected 4.32.0M through 4.32.7MAffected 4.31.0M through 4.31.9MAffected 4.30.0F to before 4.31.0Affected 4.29.0F to before 4.30.0Affected 4.28.0F to before 4.29.0Affected 4.27.1F to before 4.28.0Affected

References

https://www.arista.com/en/support/advisories-notices/security-advisory/23419-security-advisory-0134vendor-advisory

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