New York Community Bancorp sent its shares plummeting 26% on Friday after the regional lender said has discovered “material weaknesses” in the ways it tracks loan risks and that its CEO is leaving. The New York-based firm announced late Thursday that CEO Thomas Cangemi would be leaving NYCB — capping off a 27-year tenure at NYCB — and that Alessandro DiNello would take his place, effective immediately. DiNello, NYCB’s executive chairman, had been acting as the bank’s true boss since earlier this month ... One NYCB director, Hanif “Wally” Dahya, said in a Feb. 25 letter that he “did not...