What is CVE-2021-28503?

CVE-2021-28503 is a high-severity vulnerability in Arista Eos, classified under Authentication Bypass by Primary Weakness. CVSS score: 7.4/10. Published 2022-02-04.

How severe is CVE-2021-28503?

High severity. CVSS v3 base score is 7.4 out of 10.

Auth bypass in Arista Eos

CVE-2021-28503

The impact of this vulnerability is that Arista's EOS eAPI may skip re-evaluating user credentials when certificate based authentication is used, which allows remote attackers to access the device via eAPI.

Published 2022-02-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.6th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Arista Eos
Arista Networks Eos — versions EOS-4.23, EOS-4.24, EOS-4.25

Weakness classification (CWE)

References

www.arista.com/en/support/advisories-notices/security-advisories/13605-security… (Patch, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2021-28503?: CVE-2021-28503 is a high-severity vulnerability in Arista Eos, classified under Authentication Bypass by Primary Weakness. CVSS score: 7.4/10. Published 2022-02-04.
How severe is CVE-2021-28503?: High severity. CVSS v3 base score is 7.4 out of 10.