SB20260415123 - Multiple vulnerabilities in Microsoft UEFI Secure Boot

Description

This security bulletin contains information about 2 vulnerabilities.

1) Reliance on Untrusted Inputs in a Security Decision (CVE-ID: CVE-2026-0390)

CWE-ID: CWE-807 - Reliance on Untrusted Inputs in a Security Decision

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to compromise the target system.

The vulnerability exists due to reliance on untrusted input for a security decision in UEFI Secure Boot. A local administrator can bypass authentication feature and cause impersonation.

2) Improper access control (CVE-ID: CVE-2026-32220)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions in UEFI Secure Boot. A local administrator can bypass the Virtualization-based Security feature.

Remediation

Install update from vendor's website.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-0390
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-32220