Microsoft will start deprecating Secure Boot certificates for Windows systems from 2011 by June 2026. These certificates verify that a system’s initial boot processes haven’t been tampered with, ensuring security during the boot process.
The certificates are part of the Unified Extensible Firmware Interface (UEFI) and are used by Secure Boot, a standard platform in modern Windows systems. However, they don’t prevent malicious code from being executed; they only rule out potential security issues.
If you have an enterprise-managed system, your administrators will handle the process. Personal computer users should check their current version of Windows to ensure they’re up-to-date. Microsoft provides instructions for updating BIOS and motherboard manufacturer links on its website.
Expired certificates may cause security issues, but other layers of software determine how to respond. If you don’t update, you risk vulnerabilities, especially if Secure Boot is disabled.
Source: https://www.cnet.com/tech/services-and-software/windows-secure-boot-certificates-from-2011-will-be-expiring-soon-what-you-need-to-know