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

Q: How do I fix CVE-2021-36226?

my cloud os: upgrade to 5.02.104. Exact commands for each OS are on this page.

Q: Is CVE-2021-36226 being exploited?

CVE-2021-36226 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-36226 affect?

CVE-2021-36226 affects my cloud os. Severity is critical (CVSS 9.8). Western Digital My Cloud devices before OS5 do not use cryptographically signed Firmware upgrade files.

Q: How urgent is CVE-2021-36226?

Priority 58/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2021-36226 is a critical-severity flaw (CVSS 9.8) affecting my cloud os. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-347
Published	2023-02-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: westerndigital

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-02-06 14:15 UTCPublished CVE record published
2026-06-17 03:58 UTCUpdated Record last modified

westerndigital my cloud os UPGRADE

Affected: < 5.02.104

Fixed in: 5.02.104

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-36226?

my cloud os: upgrade to 5.02.104. Exact commands for each OS are on this page.

Is CVE-2021-36226 being exploited?

CVE-2021-36226 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-36226 affect?

CVE-2021-36226 affects my cloud os. Severity is critical (CVSS 9.8). Western Digital My Cloud devices before OS5 do not use cryptographically signed Firmware upgrade files.

How urgent is CVE-2021-36226?

Priority 58/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Western Digital vulnerabilities

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References

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