security peiter zatko, alleging the social media giant s leadership misled its own board, and government regulators about security vulnerabilities that could potentially open the door for foreign spying, hacking and disinformation campaigns. those are stunning, serious claims sent to congress and several federal agencies last month. our very own cnn correspondent donie o sullivan sat down with him to talk about this. here s the story. reporter: ready? yes. reporter: why are you coming forward? all my life i ve been about finding places where i can go, and make a difference. reporter: this is peiter zatko, until january of this year he was head of security at twitter, but now he s a whistle-blower, and he says twitter security problems are so grave, they are a risk to national security and democracy.