CVE intelligence and bounded remediation

CVE-2021-28494 — Arista Metamako Operating System security vulnerability

Critical CVSS 9.6

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

Severity
Critical
CVSS
9.6 (3.1)
Published
2021-09-09
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-287

Affected products

  • arista / metamako_operating_system

Matched remediation archetype

Authentication bypass and missing authentication

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.