It said more than 10 U.S. diplomats and family members had been treated for injuries, citing two senior government officials.
Five Canadian diplomats and family member have experienced similar problems, CNN reported.
The report comes amid rising tensions between the U.S. and Cuba in the wake of President Trump's announcement that he will roll back the U.S. opening to Cuba initiated by the previous administration.
The Washington Post reported in August the State Department expelled two Cuban officials from the country's embassy in Washington, D.C. in May after U.S. diplomats originally reported their symptoms.
Cuban officials pledged to investigate the incidents.
CNN said the attacks appeared to use a sophisticated weapon that "operated outside the range of audible sound."
It said the weapon causes headaches and nausea in addition to hearing loss, and that the effects were immediate.
Secretary of State Rex Tillerson has called on Cuba's government to figure out who is behind the attacks.
Cuba's government, for its part, has said it is not responsible and that it would never allow allow such weapons to be used against diplomats within its borders.