Facebook CEO Mark Zuckerberg broke his silence on the Cambridge Analytica scandal, in which a third party is accused of harvesting personal data from some 50 million unsuspecting Facebook users. In an interview with CNN, Zuckerberg apologized, discussed new company changes and said he would agree to testify before Congress. Zuckerberg also believes "bad actors" are trying to meddle in the 2018 midterm elections. NBC’s Jo Ling Kent reports from Facebook’s headquarters.