Linux Secure Boot faces disruption as Microsoft signing key nears September expiration
By
By Jake EdgeJuly 16, 2025
Summary
Linux users with Secure Boot enabled rely on a Microsoft key for booting that expires in September. Microsoft will stop using this key to sign the shim UEFI bootloader used by Linux distributions. A replacement key has been available since 2023 but may not be installed on many systems, potentially causing boot issues for Linux users after the expiration date.
Source
Hacker NewsLinux Secure Boot faces disruption as Microsoft signing key nears September expirationlwn.netKey quotes
· 3 pulledLinux users who have Secure Boot enabled on their systems knowingly or unknowingly rely on a key from Microsoft that is set to expire in September.
After that point, Microsoft will no longer use that key to sign the shim first-stage UEFI bootloader that is used by Linux distributions to boot the kernel with Secure Boot.
But the replacement key, which has been available since 2023, may not be installed on many systems; worse
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