There is no mechanism in place to prevent a bad operator to boot from a live OS image, this can lead to extraction of sensible files (such as the shadow file) or privilege escalation by manually adding a new user with sudo privileges on the machine.
Exploitability
AV:PAC:LPR:NUI:NScope
S:UImpact
C:HI:LA:H6.4/CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:HOther