If you happen to be using a Moto X 2014 Pure Edition or a Moto X 2013, you may have an update waiting for you. It appears that Motorola has begun pushing out a patch for the Stagefright exploit, along with some minor bug fixes. Here's the official word on what this update contains:
- Closes a potential security vulnerability (Stagefright)
- Bug fixes and other stability improvements
It's unclear if this one is landing for everyone at the same time, or if it's a gradual rollout. For what it's worth, however, we had to manually check for the 4.3MB update to pull it down, so that would be your best bet. To do so, head to your Settings menu then go to "About Phone" and tap "System Updates."