How’s this for an undocumented feature? Apple’s newer MacBook, MacBook Air and MacBook Pro notebooks have a security flaw that can allow hackers to remotely prevent the batteries from charging. Better yet, hackers can exploit the same flaw and remotely cause batteries to explode. Apple laptops’ new “smart” battery technology is intended to provide added control over power management, and it does just that. Unfortunately, it also gives hackers added control because the microcontroller chip that ships in recent Apple laptops can be accessed remotely using a default password shared by each and every notebook. Charlie Miller, the security expert who discovered the vulnerability, plans to showcase the flaw next month at the Black Hat security conference. There, Miller will show that he is able to access the battery controller remotely and cause it to refuse a charge, or even heat up until it catches fire and explodes. “These batteries just aren’t designed with the idea that people will mess with them,” Miller told Forbes last week. “What I’m showing is that it’s possible to use them to do something really bad.” Thankfully, the security expert also intends to showcase a fix for the flaw, which Apple will hopefully implement as soon as possible.