Right after the latest security update on macOS Mojave 10.14.6, all virtual machines of Parallels Desktop 15.1.4 (Pro) failed to connect to Internet: 1) VMs cannot obtain their dynamic IP addresses from the Mac host, 2) Parallels didn't update the entries of running VMs in Mac's /etc/hosts, and 3) all kinds of VMs are affected: Windows and Linux. I don't know what's happened there, but seems a very bad one that needs a fix immediately.