The security issue (CVE-2020-11884) patched in Ubuntu 20.04 LTS (Focal Fossa) was discovered by security researcher Al Viro in the Linux kernel for s390x systems. Apparently, the Linux kernel failed to perform page table upgrades for kernel sections that use a secondary address mode. This could allow a local attacker to either crash the vulnerable, unpatched system by causing a denial of service or execute arbitrary code. In other words, systems running on the IBM Z (s390x) architecture could be made to crash or run programs as root (system administrator) under certain conditions.