Critical (9.8) in westerndigital my cloud os. EPSS 0.7% chance of exploitation in the next 30 days.
An authentication bypass issue via spoofing was discovered in the token-based authentication mechanism that could allow an attacker to carry out an impersonation attack.
This issue affects My Cloud OS 5 devices: before 5.26.202.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.7% chance of exploitation in the next 30 days; higher than 52% of CVEs (scores of 2026-10-31)