However, three other persons swam to safety, the police said.
The incident happened near Temtha ghat under the jurisdiction of Parbatta police station of the district, Gogri Sub-Divisional Police Officer (SDPO) Rajan Kumar Sinha said.
The boat was ferrying passengers more than its capacity. It was carrying around 10 passengers, at least four persons above its capacity, the SDPO said, adding, that the boat capsized due to strong winds and overloading.
The passengers had gone to collect fodder in the riverine area, he said, adding, that bodies of three persons were fished out from the river with the help of local divers.
Efforts were on to trace the missing persons, he said.