Microsoft’s 2011 UEFI Certificate Authority Expired Yesterday

A blog entry on einval.com reports the expiration of Microsoft’s old UEFI Certificate Authority. The CA was originally created in 2011 to sign firmware for secure boot. The author notes that the certificate’s validity ended yesterday. The expiration means the CA can no longer be used to issue trusted UEFI signatures. Existing devices that rely on the CA must transition to newer certificates. The post discusses potential impacts on legacy hardware that still trusts the old CA. It advises system administrators to audit firmware signing chains for compliance. The article suggests monitoring future Microsoft updates for replacement certificates.