Decades-old Flaws Expose Weakness in UEFI Secure Boot System

WHO:

TechRadar - Experts in cybersecurity have identified vulnerabilities in UEFI Secure Boot.

Ars Technica - Microsoft is involved due to its Secure Boot technology.

WHAT:

TechRadar - Almost a dozen vulnerable UEFI shim bootloaders have been discovered and revoked.

Ars Technica - The Secure Boot system has been compromised for over a decade without detection.

WHERE:

TechRadar - The vulnerabilities affect key systems that utilize UEFI Secure Boot technology.

WHEN:

Ars Technica - The vulnerabilities have existed for over ten years.

WHY:

TechRadar - Attackers can exploit these decades-old flaws to gain unauthorized access to systems.

Ars Technica - Microsoft failed to revoke old and forgotten "shims," which has made bypassing Secure Boot simple.

HOW:

TechRadar - The exploitation of the vulnerabilities does not require new methods, as existing flaws are sufficient for attackers.

Ars Technica - The process of bypassing Secure Boot involves using the unrevoked shim bootloaders.

(UPDATED July 15, 2026 14:34 UTC)

Experts in cybersecurity have uncovered vulnerabilities in UEFI Secure Boot technology, which have remained undetected for over a decade. Almost a dozen vulnerable shim bootloaders have been identified and revoked, but attackers can still exploit these long-standing flaws to gain unauthorized access to key systems. The exploitation process is alarmingly simple, as it involves using the unrevoked shim bootloaders that Microsoft failed to address.