It said 47 percent of Democratic and Democratic-leaning voters surveyed in a poll this month said they supported Clinton for the party's nomination, down 9 points since July and marking "the first time her support has dipped below 50 percent in national CNN/ORC polling on the race."
Backing for Vermont Senator Bernie Sanders, her closest rival for the Democratic nomination, has risen 10 points since July to 29 percent, CNN said. Vice President Joe Biden, who has yet to announce whether he will run, is third at 14 percent.