Here's a quick fix on how to protect your android mobile phone from the new stagefright MMS virus.
How to protect Android from Stagefright MMS virus:
Step #1: First you have to change your default messaging app. Goto Settings > More under Wireless & networks > tap on Default SMS app.
Step #2: If by default your messaging app is selected as Hangouts, change it to stock messaging app.
Step #3: If you don’t have any other option other than Hangouts, goto Google Play and install a third party messaging app.
Step #4: Open Hangouts and and tap on vertical lines on top right corner, choose settings >SMS >deselect Auto retrieve MMS.
Step #5: On the latest Android flagships by Auto retrieve MMS option is enabled in stock messaging app. Open messages app goto settings > More Settings > Multimedia messages > disable the option to Auto retrieve.
All Done! Now your Android device is protected from Stagefright MMS virus.
Bonus Tip: If you want your mobile android phone to be totally protected with any virus, then you should download an antivirus now. There's a lot of free and excellent antivirus on Google Play now that will help you protect your phone from any virus.