This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.4. A person with physical access to a Mac may be able to bypass Login Window during a software update.
https://support.apple.com/en-us/HT212529
Source: Mitre, NVD
Published: 2021-09-08
Updated: 2021-09-16
Base Score: 2.1
Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:P/A:N
Severity: Low
Base Score: 4.6
Vector: CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: Medium