Nexus users will receive mid – march security patches with an update shortly. As you know Google always care about security and privacy of consumers, so they are responsible to provide security patches and updates for each issues. They are doing that work greatly and instantly.
Google now rolling out mid-march security patches due to some security issues.
Words from Google :
“This is a known issue in the upstream Linux kernel that was fixed in April 2014 but wasn’t called out as a security fix and assigned CVE-2015-1805 until February 2, 2015. On February 19, 2016, C0RE Team notified Google that the issue could be exploited on Android and a patch was developed to be included in an upcoming regularly scheduled monthly update.”
Update your devices and stay secure.