CVE-2021-28495

Name: CVE-2021-28495
Creator: NVD / NIST
Published: 2021-09-09T13:15:09.103+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.90%

Last modified Jun 17, 2026

CVE-2021-28495 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, user authentication can be bypassed when API access is enabled via the JSON-RPC APIs. This issue affects: Arista Metamako Operating System All releases in the MOS-0.1x train MOS-0.13 and post releases in the MOS-0.1x train MOS-0.26.6 and below releases in the MOS-0.2x train MOS-0.31.1 and below releases in the MOS-0.3x train. EPSS estimates a 0.90% chance of exploitation in the next 30 days.

Description

In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, user authentication can be bypassed when API access is enabled via the JSON-RPC APIs. This issue affects: Arista Metamako Operating System All releases in the MOS-0.1x train MOS-0.13 and post releases in the MOS-0.1x train MOS-0.26.6 and below releases in the MOS-0.2x train MOS-0.31.1 and below releases in the MOS-0.3x train

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.90%

55.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Arista	Metamako Operating System	>= 0.10.0, <= 0.13.0
Arista	Metamako Operating System	>= 0.20.0, <= 0.26.7
Arista	Metamako Operating System	>= 0.30.0, < 0.32.0

References

https://www.arista.com/en/support/advisories-notices/security-advisories/12914-security-advisory-66Mitigation, Vendor Advisory
https://www.arista.com/en/support/advisories-notices/security-advisories/12914-security-advisory-66Mitigation, Vendor Advisory

Timeline

Published: Sep 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-28495?

How severe is CVE-2021-28495?

CVE-2021-28495 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.90% probability of exploitation in the next 30 days.

How do I fix CVE-2021-28495?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-28495?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST