CVE intelligence and bounded remediation

CVE-2021-36225 — Westerndigital My Cloud Os security vulnerability

High CVSS 8.8

Western Digital My Cloud devices before OS5 allow REST API access by low-privileged accounts, as demonstrated by API commands for firmware uploads and installation.

Severity
High
CVSS
8.8 (3.1)
Published
2023-02-06
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-862

Affected products

  • westerndigital / my_cloud_os

Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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