# CVE-2023-39950: efibootguard: efibootguard is a simple UEFI boot loader with support for safely switching between current and updated partition sets

CVE-2023-39950 is fixed in efibootguard on 1 platform, first by DEBIAN-CVE-2023-39950, released August 14, 2023. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-39950
- Priority: Routine
- CVSS: 5.2 (medium)
- EPSS: 0.0042
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 14, 2023

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | efibootguard Debian 12.15 (bookworm) | 0.13-2+deb12u1 | [DEBIAN-CVE-2023-39950](https://patchblox.com/security/data/fix/linux/debian-cve-2023-39950.md) | Aug 14, 2023 |
| Linux | efibootguard Debian 13.5 (trixie) | 0.15-1 | [DEBIAN-CVE-2023-39950](https://patchblox.com/security/data/fix/linux/debian-cve-2023-39950.md) | Aug 14, 2023 |
| Linux | efibootguard Debian 14 | 0.15-1 | [DEBIAN-CVE-2023-39950](https://patchblox.com/security/data/fix/linux/debian-cve-2023-39950.md) | Aug 14, 2023 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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