Multiple vulnerabilities have been found in the Ubuntu 16.04 LTS Linux 4.4 kernel. The recent update to 16.04.2 uses the 16.10 (Yakkety) Linux 4.8 kernel. So if you made the jump to 16.04.2 then check this out:
Ubuntu 16.10 Security issue
CVE-2016-9588 Discovered by Jim Mattson and Dmitry Vyukov, a flaw in the kernel’s implementation of KVM.
UbuntuFree:New Ubuntu Vulnerabilities
You can vote for Supertux Racer now at Steam Greenlight below.