An insecure default to allow UEFI Shell in EDK2 was left enabled in Ubuntu's EDK2. This allows an OS-resident attacker to bypass Secure Boot.
https://www.openwall.com/lists/oss-security/2024/02/14/4
https://nvd.nist.gov/vuln/detail/CVE-2023-48733
https://bugs.launchpad.net/ubuntu/+source/lxd/+bug/2040139
https://bugs.launchpad.net/ubuntu/+source/edk2/+bug/2040137
Source: Mitre, NVD
Published: 2024-02-14
Updated: 2024-02-15
Base Score: 10
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
Severity: Critical
Base Score: 6.7
Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Severity: Medium