The Android "Stagefright" vulnerability
Here is an
article on the "Threatpost" site about a set of remotely exploitable
media-library vulnerabilities present on vast numbers of Android devices.
"An attacker in possession of their target’s phone number could send
an MMS or even a Google Hangouts message to an affected device that
triggers the vulnerability before the victim has a chance to open the
message. In some cases, the attack would delete the MMS in question,
leaving behind only a notification that a message was sent."