revealed that the United States intercepted messages between Ayman al-Zawahri, who succeeded Osama bin Laden as the head of Al Qaida, and Nasser al-Wuhayshi, the head of the Yemen-based Al Qaida in the Arabian Peninsula, discussing an imminent terrorist attack [0]
And as a result, they may have changed communication methods.
He's had other questionable discloses as well.
0. http://www.nytimes.com/2013/09/30/us/qaeda-plot-leak-has-und...