A flaw was found in the grub2-set-bootflag utility of grub2. A local attacker could run this utility under resource pressure (for example by setting RLIMIT), causing grub2 configuration files to be truncated and leaving the system unbootable on subsequent reboots.
https://seclists.org/oss-sec/2019/q4/101
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-14865