A stranger stabbed a man in the head in an unprovoked attack in the Bronx over the weekend, authorities said. 

The 49-year-old victim was on St. Paul’s Place near Fulton Avenue in Claremont Village around 5 p.m. Sunday when the assailant approached and lunged at his head with a knife — without saying a word, cops said. 

The victim was taken to St. Barnabas Hospital with a severe cut on his head. 

The attacker ran off, heading south on Fulton Avenue, cops said. 

He is shown in surveillance footage released by cops late Sunday.