Quoting https://insights.ubuntu.com/2018/01/04/ubuntu-updates-for-the-meltdown-spectre-vulnerabilities/
Ubuntu has also written a KB here; https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SpectreAndMeltdown
Seems like we will get the kernels to upstream ubuntu january 9th.
Ubuntu users of the 64-bit x86 architecture (aka, amd64) can expect updated kernels by the original January 9, 2018 coordinated release date, and sooner if possible. Updates will be available for:
Ubuntu 17.10 (Artful) — Linux 4.13 HWE
Ubuntu 16.04 LTS (Xenial) — Linux 4.4 (and 4.4 HWE)
Ubuntu 14.04 LTS (Trusty) — Linux 3.13
Ubuntu has also written a KB here; https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SpectreAndMeltdown
Seems like we will get the kernels to upstream ubuntu january 9th.