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CVE-2023-39950 Detail


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.


CVSS 3.x Severity and Metrics:

Base Score:  5.2 MEDIUM
Vector:  CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  6.1 MEDIUM
Vector:  CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/siemens/efibootguard/blob/master/docs/API.md Third Party Advisory 
https://github.com/siemens/efibootguard/blob/master/docs/TOOLS.md Third Party Advisory 
https://github.com/siemens/efibootguard/blob/master/docs/TOOLS.md#setting-user-variables Third Party Advisory 
https://github.com/siemens/efibootguard/security/advisories/GHSA-j6pp-7g99-24m7 Third Party Advisory 
https://github.com/siemens/efibootguard/tags Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-20 Improper Input Validation Provider acceptance level GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
NVD Published Date:
NVD Last Modified:
GitHub, Inc.