Right on schedule, Google has released the December 2019 security updates for its Pixel phones. The new updates should begin rolling out over the air to the Pixel 4 and 4 XL, Pixel 3 and 3 XL, Pixel 3a and 3a XL, Pixel 2 and 2 XL, and Pixel and Pixel XL, so if you've got one of those models, be on the lookout or check for your update manually.
Google has also posted the factory images and OTA images for the December 2019 security updates if you'd prefer to update your Pixel that way.
According to Google, the 2019-12-01 security update patches vulnerabilities related to the framework, media framework, and system. There are some media codec fixes included in Google Play system updates, too. The 2019-12-05 security level adds more fixes, including ones for vulnerabilities related to the framework, system, kernel components, Qualcomm components, and Qualcomm closed source components.
Pixel owners have a few other vulnerability patches to look forward to. They fix bugs related to the system and kernel components.
Finally, it's worth noting that this month's update will be the final one for the original Pixel and Pixel XL. Google recently said that it was working on "one final software update" for its original Pixel phones, telling The Verge that the December update would include "a variety of updates" from November and December that were pushed to other Pixel phones.
The original Pixel and Pixel XL launched way back in 2016 and Google had said that they'd get guaranteed security updates through October 2019, so that explains why update support for the phones is ending now. It's always kind of a bummer to see a phone stop getting software updates, but the original Pixel phones had a pretty solid run, and the good news is that at least they're getting one last big update for anyone happily rocking a Pixel or Pixel XL.