SecureBoot

Winsage
May 21, 2026
Users have observed a new folder named “SecureBoot” in the Windows system folder following the installation of Windows 11's May update (KB5089549). This update may cause installation issues for some devices and introduces a directory that contains example scripts for IT professionals to manage Secure Boot certificate updates. Windows Secure Boot certificates are set to expire next month, and outdated certificates will lead to loss of support starting in June, potentially compromising Secure Boot functionality. Microsoft is distributing new certificates through Windows Update. The SecureBoot folder does not require individual users to take action, and deleting it is discouraged as it may cause complications with future Windows updates.
Winsage
June 12, 2025
Recent findings have identified two vulnerabilities in various UEFI BIOS versions from multiple manufacturers, compromising the SecureBoot mechanism. These vulnerabilities allow attackers to bypass SecureBoot protections and replace firmware, particularly in Insyde BIOSes. The issues stem from unprotected NVRAM variables, specifically the "IhisiParamBuffer," which can be manipulated to execute unsigned UEFI binaries. Affected UEFI applications include "DTBios" and "BiosFlashShell" from DTResearch, with a CVSS score of 8.2. Microsoft has added 14 new hashes to its DBX database to mitigate these risks. Additionally, a vulnerability in the Insyde H2O UEFI firmware app allows attackers to infiltrate digital certificates due to the insecure handling of the "SecureFlashCertData" variable, which is incorrectly treated as trusted memory. This flaw, known as "Hydroph0bia," has a CVSS score of 7.8 and enables unauthorized execution of firmware certified with manipulated certificates. Manufacturers are urged to provide firmware updates to address these vulnerabilities, as inconsistent support for locking UEFI variables raises security concerns.
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