October security patch for Nexus and Pixel devices released, factory images available for download
Along with the update, Google published the security bulletin that lists the most important issues it's supposed to patch. Overall, there are 14 security problems that have been addressed in this update, but other small issues have been resolved as well.
The update is pushed OTA (over the air) in stages, so it may take a few days to reach all compatible Nexus and Pixel devices. However, Google already released the factory images and OTA files that contain the October security update, so those who don't feel like waiting can flash them right away.
As for those who don't own Nexus or Pixel devices, you'll probably have to wait a while longer until other companies start pushing the October security update.
The following Google devices are now eligible to receive the latest security patch: Pixel XL, Pixel, Pixel C, Nexus 6P, Nexus 5X, Nexus 6, and Nexus 9 (LTE and Wi-Fi only).