CVE-2021-36226

CRITICALNVD 9.89.8—

9.8

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

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 45.6%
KEV: Not listed

Published

February 6, 2023

Last Modified

March 26, 2025

Advisory Details (3)

Auto-updated May 25, 2026

🔬 Proof of concept available. No patch confirmed yet.

generic

https://www.youtube.com/watch?v=vsg9YgvGBec

generic

Another 0-Day Looms for Many Western Digital Users – Krebs on Security

https://krebsonsecurity.com/2021/07/another-0-day-looms-for-many-western-digital-users/

generic🟡 PoC Available

PoC/advisories/Pwn2Own/Tokyo_2020/weekend_destroyer/weekend_destroyer.md at master · pedrib/PoC · GitHub

https://github.com/pedrib/PoC/blob/master/advisories/Pwn2Own/Tokyo_2020/weekend_destroyer/weekend_destroyer.md

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-347Improper Verification of Cryptographic Signature

Data Freshness Timeline

(refreshed 12× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-25 07:23 UTCEG score recompute

Frequently asked(5)

What is CVE-2021-36226?

CVE-2021-36226 is a critical vulnerability published on February 6, 2023. Western Digital My Cloud devices before OS5 do not use cryptographically signed Firmware upgrade files.

When was CVE-2021-36226 disclosed?

CVE-2021-36226 was first published in the National Vulnerability Database on February 6, 2023, with the most recent update on March 26, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-36226 actively exploited?

CVE-2021-36226 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 45.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-36226?

CVE-2021-36226 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2021-36226?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-36226, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-36226

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CVE-2021-36226

📅 Published

🔄 Last Modified

📋 Advisory Details (3)