What is CVE-2026-121368?

CVE-2026-121368 is a high-severity vulnerability in Arista Networks Eos, classified under Out-of-bounds Write. CVSS score: 8.6/10. Published 2026-11-10.

How severe is CVE-2026-121368?

High severity. CVSS v3 base score is 8.6 out of 10.

Buffer overflow in Arista Networks Eos

CVE-2026-121368

On affected platforms running Arista EOS with Bidirectional Forwarding Detection (BFD) configured to use keyed MD5 or keyed SHA1 authentication, an unauthenticated attacker with network adjacency (direct or multi-hop) to a BFD-enabled interface can send a specially crafted BFD packet resulting in a system reboot.

Vulnerability class: Buffer Overflow

Published 2026-11-10.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

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

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

www.arista.com/en/support/advisories-notices/security-advisory/25028-security-a… (vendor-advisory)

Frequently asked questions

What is CVE-2026-121368?: CVE-2026-121368 is a high-severity vulnerability in Arista Networks Eos, classified under Out-of-bounds Write. CVSS score: 8.6/10. Published 2026-11-10.
How severe is CVE-2026-121368?: High severity. CVSS v3 base score is 8.6 out of 10.