Hopefully google paid and/or blackmailed carriers into filtering these mms messages. I think that's really the only possible remediation when at least 50% of android phones are functionally un-updatable.
It's also probably possible to extend the patches to detect malicious input.
Someone could probably also create a video with a payload to hot patch libstagefright.
This is brilliant. Assuming that it doesn't cause further problems.
Here's a more modest idea: Google should immediately issue update for Hangouts and Messenger app that at least disables automatic MMS retrieval. Many users have automatic updates for those apps turned on or maybe at least they'll see a notification about app needing approval to update.