What is CVE-2026-121291?

CVE-2026-121291 is a high-severity vulnerability in Arista Networks Eos, classified under CWE-696. CVSS score: 8.2/10. Published 2026-11-10.

How severe is CVE-2026-121291?

High severity. CVSS v3 base score is 8.2 out of 10.

Vulnerability in Arista Networks Eos

CVE-2026-121291

A crafted Error Report can leave EOS stuck believing that a cache reset is in progress, preventing ROA publication, withdrawal reconciliation, and BGP origin-validation updates.

Published 2026-11-10.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Arista Networks Eos — versions 4.37.0F

Weakness classification (CWE)

CWE-696

References

www.arista.com/en/support/advisories-notices/security-advisory/25044-security-a… (vendor-advisory)

Frequently asked questions

What is CVE-2026-121291?: CVE-2026-121291 is a high-severity vulnerability in Arista Networks Eos, classified under CWE-696. CVSS score: 8.2/10. Published 2026-11-10.
How severe is CVE-2026-121291?: High severity. CVSS v3 base score is 8.2 out of 10.