Google is just the best when it comes to giving people the best. In this context we mean that it is not even a month since the company released the Android 4.4.3 update for Nexus devices across the globe and the Android 4.4.4 update is rolling out. The Android 4.4.4 update for Nexus devices does not have major security updates but there are small changes here and there.
There is a change-log that has been published by Sprint which states that the Android 4.4.4 update is a security fix. As per Android Police, the update is said to hold a patch for an OpenSSL bug which would have allowed a man-in-the-middle attack that is similar to the Heartbleed bug that was seen in the Android 4.4.3 update. In case, you have used Towelroot to root your Nexus device then your device will remain unaffected.