A feature in LXD (LP#1829071), affects the default configuration of Ubuntu Server which allows privileged users in the lxd group to escalate their privilege to root without requiring a sudo password.
https://ubuntu.com/security/CVE-2023-5536
https://discourse.ubuntu.com/t/easy-multi-user-lxd-setup/26215/4
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-5536