CVE-2023-39950 Insufficient input validation in efibootguard
Insufficient input validation in efibootguard allows attackers to inject code or cause crashes via manipulated bootloader environment files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-39950?
CVE-2023-39950 is a medium-severity code injection vulnerability in siemens efibootguard, published on 14 Aug 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-20
Which versions are affected by CVE-2023-39950?
It affects 1 product.
Products include Siemens Efibootguard.
How do I fix CVE-2023-39950?
Upgrade to a fixed version.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2023-39950 being exploited?
There is no known exploitation of CVE-2023-39950 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2023-39950, GHSA-j6pp-7g99-24m7, UBUNTU-CVE-2023-39950.