CVE-2026-2379Network attack vector

IPsec instability via reused security associations

Published Jun 5, 2026 · Updated Jun 5, 2026

Resource-lifecycle flaw in Arista EOS 4.27.1F through 4.34.3M allows remote attackers to destabilize IPsec tunnel communication. EOS re-establishes a tunnel with existing Security Associations after physical interface flaps or certain agent restarts, creating endpoint sequence-number mismatches. Exposure is limited to listed hardware-IPsec platforms with anti-replay detection disabled; the feature is enabled by default, and the resulting communication can become unstable.

CVSS severity5.9
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource-lifecycle flaw in Arista EOS 4.27.1F through 4.34.3M allows remote attackers to destabilize IPsec tunnel communication. EOS re-establishes a tunnel with existing Security Associations after physical interface flaps or certain agent restarts, creating endpoint sequence-number mismatches. Exposure is limited to listed hardware-IPsec platforms with anti-replay detection disabled; the feature is enabled by default, and the resulting communication can become unstable.

The record

CVE
CVE-2026-2379
Published
Jun 5, 2026
Updated
Jun 5, 2026
Vendor
Arista Networks
Product
Arista Extensible Operating System (EOS)
Classifications
CWE-672
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.27.1F <4.28.0
  2. Affected versionversion=4.28.0F <4.29.0
  3. Affected versionversion=4.29.0F <4.30.0
  4. Affected versionversion=4.30.0F <4.31.0
  5. Affected versionversion=4.31.0M <=4.31.9M
  6. Affected versionversion=4.32.0M <=4.32.7M
  7. Affected versionversion=4.33.0M <=4.33.5M
  8. Affected versionversion=4.34.0 <=4.34.3M

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Arista Networks · Arista Extensible Operating System (EOS)version=4.27.1F <4.28.0; version=4.28.0F <4.29.0; version=4.29.0F <4.30.0; version=4.30.0F <4.31.0; version=4.31.0M <=4.31.9M; version=4.32.0M <=4.32.7M; version=4.33.0M <=4.33.5M; version=4.34.0 <=4.34.3M

Published CVSS scores

8.2Arista NetworksCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
5.9Arista NetworksCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-672Operation on a Resource after Expiration or Release

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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