openSUSE

Eleven Old Microsoft-Signed UEFI Shims Enable Bypass of Secure Boot on Linux Systems Still Trusting Microsoft Corporation UEFI CA 2011

Eleven legacy UEFI shim bootloaders signed by Microsoft, all version 0.9 or earlier, can be abused to bypass UEFI Secure Boot on systems whose firmware still trusts the Microsoft Corporation UEFI CA 2011 certificate. Attackers who manage to place one of these vulnerable shims in the boot path can execute arbitrary code before the operating system loads, enabling bootkits, persistence, and kernel-level compromise with minimal visibility to traditional EDR tools. The issue stems not from a new kernel bug but from the continued validity of old, correctly signed binaries that have not yet been revoked in the DBX database. Microsoft has already issued DBX revocation updates, yet administrators must first upgrade shim, GRUB, and other boot components to modern versions that support SBAT before applying the revocations to avoid bricking systems. Affected implementations include Red Hat Enterprise Linux 7.2, CentOS 7.2, Oracle Linux 7.2, openSUSE, baramundi Management Suite up to 2024R1, WipeDrive 8.0.0–8.1.3, PC Doctor Service Center, and Abitti 1. The problem is tracked under CVE-2026-8863 and CVE-2026-10797, with public references available from The Hacker News, CERT/CC VU#616257, NIST NVD, and Help Net Security.