The start of a new month means new security patches for Android devices, and that's exactly what Google has provided us with today, the second day of January.
Google today unleashed the January 2018 Android security patches. There are many fixes included in the 2018-01-01 patch level, including one for the Android runtime and several more for the Media framework and the System.
There's also a 2018-01-05 security patch level that includes a handful more fixes, including one related to HTC components and one for LG components.
For you Nexus and Pixel owners, Google also offers a dedicated Pixel/Nexus Security Bulletin. These phones will be updated to the 2018-01-05 patch level, which should start going out over the air today. If you've got a Nexus or Pixel device, your phone should get its update in the coming days.
If you'd prefer to update your Pixel or Nexus device now, Google does offer factory images and full OTA images that you can download and sideload onto your device.