Do you use Android phones or tablets? Then this is for you.
There is a critical security vulnerability in an OS library that can lead to arbitrary code execution. All that it takes to do this is your phone number and a specially-crafted MMS. Depending on what application you use for SMS/MMS, you won't even receive a notification that anything happened; on other applications, you need tto open the MMS before it activates.
This article explains how you can mitigate the issue until (if) your phone is updated. You will no longer download MMS automatically. Should you receive one from an unknown number, ignore it; should you receive one from someone you know, confirm that this person sent this message before opening it.
Or, you know, use one of the many better alternatives.
Tablets without 3G or LTE won't be affected because you can't receive MMS on them anyway.
