What is CVE-2020-28971?

CVE-2020-28971 is a critical-severity vulnerability in Westerndigital My Cloud Ex2 Ultra, classified under Improper Authentication. CVSS score: 9.8/10. Published 2020-12-01.

How severe is CVE-2020-28971?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Auth bypass in Westerndigital My Cloud Ex2 Ultra

CVE-2020-28971

An issue was discovered on Western Digital My Cloud OS 5 devices before 5.06.115. A NAS Admin authentication bypass vulnerability could allow an unauthenticated user to execute privileged commands on the device via a cookie, because of insufficient validation of URI paths.

Vulnerability class: Broken Authentication

Published 2020-12-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.038 (89.7th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.038 · newest: 0.038 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

support.wdc.com/downloads.aspx (Patch, Vendor Advisory)
www.westerndigital.com/support/productsecurity/wdc-20009-os5-firmware-5-06-115 (Vendor Advisory)
www.zerodayinitiative.com/advisories/ZDI-20-1447/ (VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2020-28971?: CVE-2020-28971 is a critical-severity vulnerability in Westerndigital My Cloud Ex2 Ultra, classified under Improper Authentication. CVSS score: 9.8/10. Published 2020-12-01.
How severe is CVE-2020-28971?: Critical severity. CVSS v3 base score is 9.8 out of 10.