Red Hat and CentOS can't boot - BootHole patches

Do NOT apply the GRUB2 security patches (RHSA-2020:3216 or RHSA-2020:3217) until these issues have been resolved.

If you administer a RHEL or CentOS system and believe you may have installed these patches, do not reboot your system. 

Fix-Revert

Downgrade the affected packages using 

sudo yum downgrade shim\* grub2\* mokutil

and configure yum not to upgrade those packages by temporarily adding:

exclude=grub2* shim* mokutil 

to /etc/yum.conf.


If you've already applied the patches and attempted (and failed) to reboot, boot from an RHEL or CentOS DVD in Troubleshooting mode, set up the network, then perform the same steps outlined above in order to restore functionality to your system

Ubuntu and Debian

Package grub2 updates already been pushed.