PatchSiren cyber security CVE debrief

CVE-2025-8873 Arista Networks CVE debrief

CVE-2025-8873 is a HIGH severity vulnerability in Arista EOS with IPsec configured. A specially crafted packet can cause the dataplane to stop processing all IPsec traffic. The control plane may detect this condition and attempt to reset the IPsec processing pipeline. After reset, traffic may not resume being processed. There is no impact to non-IPsec traffic or to IPsec traffic not originating or terminating on the system. This issue was reported by an Arista customer.

Vendor: Arista Networks
Product: EOS
CVSS: HIGH 8.7
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-04
Original CVE updated: 2026-06-05
Advisory published: 2026-06-04
Advisory updated: 2026-06-05

Who should care

Users of Arista EOS with IPsec configured should be aware of this vulnerability and take steps to mitigate it.

Technical summary

On affected platforms running Arista EOS with IPsec configured, a specially crafted packet can cause the dataplane to stop processing all IPsec traffic. The control plane may detect this condition, and attempt to reset the IPsec processing pipeline. After reset traffic may not resume being processed. There is no impact to non-IPsec traffic or to IPsec traffic not originating or terminating on the system.

Defensive priority

HIGH

Recommended defensive actions

Apply the patch or workaround provided by the vendor (see resourceLinkAnnotations 'ref-4')
Review and update IPsec configurations to prevent exploitation

Evidence notes

The vendor is Arista, as indicated by the source reference (resourceLinkAnnotations 'ref-4') and evidence in the vendor field.

Official resources

CVE-2025-8873 was published on 2026-06-04T23:16:48.413Z and modified on 2026-06-05T15:02:34.977Z.