Any questions relating to status updates, or asking if anything is going to be patched for these vulnerabilities should be closed as duplicates of this question.
Meltdown and Spectre are in the news right now and sound pretty severe. I don't see any security updates from Ubuntu that cover these vulnerabilities.
What is Ubuntu doing about these vulnerabilities, and what should Ubuntu users be doing?
These are CVE-2017-5753, CVE-2017-5715 and CVE-2017-5754.