Buffer overflow in Arista Networks Eos
CVE-2026-121289
On affected platforms running Arista EOS with BGP configured, a specially crafted packet can cause the BGP agent to crash. Successful exploitation causes the BGP agent process to terminate, resulting in the loss of all BGP sessions on the affected device and possible disruption to network routing until the process recovers. Due to the nature of the vulnerability, it may also be possible for a sophisticated attacker to achieve arbitrary code execution, which could compromise the confidentiality and integrity of the affected system.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-121289?
- CVE-2026-121289 is a critical-severity vulnerability in Arista Networks Eos, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-11-10.
- How severe is CVE-2026-121289?
- Critical severity. CVSS v3 base score is 9.8 out of 10.