Stagefright was the scariest Android vulnerability to come along in some time. A bug in Android's "Stagefright" media library could, if fully weaponized, allow an attacker to execute malicious code just by sending an MMS message to a user. Luckily exploit mitigation techniques in newer versions of Android stopped the Stagefright vulnerability from becoming a pwning free-for-all, but the bug shined a bright light on Android's sub-par security situation.
The publicity got the Android device ecosystem—Google, OEMs, and carriers—to at least start paying attention to delivering security updates to users in a timely manner. Google, Samsung, and LG scrambled to get fixes out to their flagship devices and promised monthly security updates for their devices. That was 36 days ago.
Today, Google has posted the first of those monthly security updates for Nexus device owners. The Nexus system image page added Android 5.1.1 build "LMY48M" for the Nexus 4, 5, 6, 7, 9, and 10, along with build "LMY48N" for the Android TV-based Nexus Player. LMY48M hit Google's public AOSP repository yesterday (August 9).