Security updates for Thursday

Security updates have been issued by Fedora (log4j and quaternion), Mageia (gnome-shell and singularity), SUSE (libsndfile, libvirt, net-snmp, and python-Babel), and Ubuntu (linux, linux-aws, linux-aws-5.11, linux-azure, linux-azure-5.11, linux-gcp, linux-gcp-5.11, linux-hwe-5.11, linux-kvm, linux-oracle, linux-oracle-5.11, linux-raspi, linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gke, linux-gke-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux, linux-aws, linux-aws-hwe, linux-azure-4.15, linux-dell300x, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm, linux-oracle, linux-raspi2, linux-snapdragon, linux, linux-aws, linux-kvm, linux-lts-xenial, linux-oem-5.10, and linux-oem-5.14).