It's that time of month again where Google releases security fixes for Android. The Android Security Bulletin for February 2017 has just been posted, addressing 35 critical bugs - most of which affect Nexus and Pixel devices. The most severe issue that the February patch level fixes could enable remote code execution when processing media files.
There are two security patch levels for February - the first of which (Feb 1) addresses the above media vulnerability and a few others, while the second(Feb 5) includes fixes for the rest. All devices that include the Feb 5 patch level also include all previous patches, including the Feb 1 fixes. As always, it's up for manufacturers to push these security updates to their devices.
Nexus and Pixel owners can expect an OTA in the coming days with the security fixes. If you don't prefer waiting, you can flash the updated system images yourself from the second link below.
Source: Android Security Bulletin , OTA images