There have been several explosions outside the university since the army ousted Islamist president Mohamed Morsi in 2013. Five policemen were wounded in an explosion there in November.
All of the attacks, including Saturday's, have been claimed by Cairo-based Ajnad Misr (Soldiers of Egypt).
The rudimentary bomb was placed at the exit of a metro station that serves the university, a police official said.
Health ministry spokesman Hossam Abdel Ghaffar said the wounded were "in stable condition".