In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, authentication…

published 2021-09-09 5y ago modified 2026-06-17 4mo ago also EUVD-2021-15170

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits: 0; none known

In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, authentication is bypassed by unprivileged users who are accessing the Web UI. This issue affects: Arista Metamako Operating System MOS-0.34.0 and prior releases

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Exploit prediction

0.88% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	6.5	AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

Arista Metamako Operating System

Classification

Weakness

CWE-287 Improper Authentication

References

arista.com /en/support/advisories-notices/security-advisories/12916-security-advisory-68
mitigation, vendor-advisory

Sources

CVE List CVE-2021-28494
NVD CVE-2021-28494

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