Security readout for executives and security teams
Plain-English summary
Low-privileged users on Western Digital My Cloud devices before OS5 could access sensitive REST API functions, including firmware upload and installation paths. For a business, this means a basic account may have enough reach to compromise the device’s data, integrity, and availability.
Executive priority
Treat as a high-priority exposure review for any My Cloud devices still in use. Prioritize internet-exposed, shared-user, or business-critical storage devices first.
Technical view
CVE-2021-36225 is a missing authorization issue in Western Digital My Cloud pre-OS5 REST APIs. The CVSS 3.1 score is 8.8 with network access, low complexity, low privileges, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely where Western Digital My Cloud devices run pre-OS5 software and have low-privileged user accounts. The provided CVE data does not include exact model, CPE, or version ranges.
Exploitation context
The source bundle includes public coverage and technical demonstration references, but CISA KEV is false and no cited source here confirms active exploitation for this CVE.
Researcher notes
The provided affected-product metadata is incomplete, despite the description naming My Cloud before OS5. Validate model applicability against vendor materials before asserting fleet-wide impact.
Mitigation direction
- Inventory Western Digital My Cloud devices and identify any running pre-OS5 software.
- Check Western Digital guidance for supported OS5 or firmware remediation paths.
- Restrict device management and REST API access to trusted networks.
- Remove unnecessary low-privileged accounts and review remaining account permissions.
- Monitor for unexpected firmware upload, installation, or configuration-change activity.
Validation and detection
- Confirm each My Cloud device model and software generation from asset records.
- Verify whether each device is running OS5 or an earlier release.
- Review user accounts for low-privileged access that is still business-required.
- Check network exposure for device web and API management interfaces.
- Review logs or administrative history for unexpected firmware-related changes.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-862: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-36225 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://krebsonsecurity.com/2021/07/another-0-day-looms-for-many-western-digital-users/CVE reference
- https://www.youtube.com/watch?v=vsg9YgvGBecCVE reference
- https://github.com/pedrib/PoC/blob/master/advisories/Pwn2Own/Tokyo_2020/weekend_destroyer/weekend_destroyer.mdCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Authorization
Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.