Servers are usually on LTS versions. Ubuntu 16.04 is on 4.4 last time I checked. My Android 7.0 phone is on 3.10.84, last updated in February.
Edit: Ubuntu's tracker is at https://people.canonical.com/~ubuntu-security/cve/2016/CVE-2...
Edit: Ubuntu's tracker is at https://people.canonical.com/~ubuntu-security/cve/2016/CVE-2...