Citing local activist Ahmad al-Ramadan, the All 4 Syria website said IS jihadists detained the young man in a restaurant in Deir Ezzor after he allegedly told its owner that Kurdish forces were approaching the city.
The IS militants then stitched up the man's mouth, shut him in a cage and drove around the city in a pick-up truck with the caged man inside, said the website, which is close to the Syrian opposition.
It was not the first time that IS militants meted out such punishment. Activists have reported other cases in villages around Deir Ezzor, which is under IS control.
Kurdish and Yazidi forces have advanced to the village of Abu Kashab, some 70 km from Deir Ezzor, creating unease among IS fighters occupying the city, All 4 Syria said.