Howto Patch Ubuntu Server For Meltdown And Spectre

Run the following command

sudo apt-get update && sudo apt-get dist-upgrade

Check your current ubuntu version.

lsb_release -a

Check if either of the following kernels are installed (as of 14 Jan 2018).

The following command list all installed kernels.

dpkg --list | grep linux-image

Check current kernel.

uname -r

If latest kernel is installed (dpkg --list | grep linux-image) but current kernel (uname -r) is not the latest, reboot your server.

sudo reboot

After reboot, check current kernel again.

DigitalOcean

If you created your DigitalOcean Droplet more than 2 years ago, you might have an externally managed kernels.

In the past, kernels for DigitalOcean Droplets were managed outside of the Droplets themselves inside the DigitalOcean control panel.

Later DigitalOcean Droplet use Modern DigitalOcean Kernel Management.

Changes in DigitalOcean's backend infrastructure have lead to a more modern process that allows users to manage kernels within the Droplet.

If you are using an old droplet and realize the above instruction doesn't update the Kernel to latest after reboot, refer to How To Update a DigitalOcean Server's Kernel.

At Droplet control panel page, select Kernel. Select GrubLoader v0.2 as the kernel.
Power off the server (rebooting will not change the kernel). Either sudo poweroff or select Power -> Power off.
Power on the server using Power -> Power on (it might take a few minutes for the page to update after poweroff)

Check your current kernel and it should be the latest (if you already executed sudo apt-get update && sudo apt-get dist-upgrade)

References: