This article highlights the issues that older computer systems will encounter when the Secure Boot Certificate expires ...
Your Linux PC has a Secure Boot problem - what to do first (and the workaround to avoid) ...
Certificate Expiration: The KEK CA 2011 certificate expired on June 24, 2026, stopping unpatched systems from receiving new Secure Boot revocations. Trust Chain Preservation: The update replaces 2011 ...
Fortunately, it's a 5 minute fix.