{"cve":"CVE-2023-39950","nvd":{"published":"2023-08-14T21:15:13.420","modified":"2026-06-17T06:13:00.833","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","score":5.2},"cwes":["CWE-20"],"references":["https://github.com/siemens/efibootguard/blob/master/docs/API.md","https://github.com/siemens/efibootguard/blob/master/docs/TOOLS.md","https://github.com/siemens/efibootguard/blob/master/docs/TOOLS.md#setting-user-variables","https://github.com/siemens/efibootguard/security/advisories/GHSA-j6pp-7g99-24m7","https://github.com/siemens/efibootguard/tags"],"products":["siemens:efibootguard"],"source":"nvd","synced_at":"2026-10-19T21:39:14.809778102+00:00"},"epss":{"cve":"CVE-2023-39950","score":0.00423,"percentile":0.36649,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}