CVE-2023-39950

Publication date 14 August 2023

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

5.2 · Medium

Score breakdown

efibootguard is a simple UEFI boot loader with support for safely switching between current and updated partition sets. Insufficient or missing validation and sanitization of input from untrustworthy bootloader environment files can cause crashes and probably also code injections into `bg_setenv`) or programs using `libebgenv`. This is triggered when the affected components try to modify a manipulated environment, in particular its user variables. Furthermore, `bg_printenv` may crash over invalid read accesses or report invalid results. Not affected by this issue is EFI Boot Guard’s bootloader EFI binary. EFI Boot Guard release v0.15 contains required patches to sanitize and validate the bootloader environment prior to processing it in userspace. Its library and tools should be updated, so should programs statically linked against it. An update of the bootloader EFI executable is not required. The only way to prevent the issue with an unpatched EFI Boot Guard version is to avoid accesses to user variables, specifically modifications to them.

Status

Package Ubuntu Release Status
efibootguard 25.04 plucky
Needs evaluation
24.10 oracular
Needs evaluation
24.04 LTS noble
Needs evaluation
23.10 mantic Ignored end of life, was needs-triage
23.04 lunar Ignored end of life, was needs-triage
22.04 LTS jammy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Ignored end of standard support
16.04 LTS xenial Ignored end of standard support
14.04 LTS trusty Ignored end of standard support

Severity score breakdown

Parameter Value
Base score 5.2 · Medium
Attack vector Physical
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact High
Availability impact Low
Vector CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L