SB2026061280 - Multiple vulnerabilities in Microsoft UEFI Secure Boot

Description

This security bulletin contains information about 2 vulnerabilities.

1) Protection Mechanism Failure (CVE-ID: CVE-2026-45656)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/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 bypass implemented security restrictions.

The vulnerability exists due to insufficient implementation of security measures in UEFI Secure Boot. A local user can bypass a security feature on the system.

2) Reliance on Component That is Not Updateable (CVE-ID: CVE-2026-8863)

CWE-ID: CWE-1329 - Reliance on Component That is Not Updateable

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/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 bypass implemented security restrictions.

The vulnerability exists due to insufficient implementation of security measures in UEFI Secure Boot. A local user can bypass a security feature on the system.

Remediation

Install update from vendor's website.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45656
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-8863