The explosion, caused by a sticky bomb, took place on Friday, according to officials.
Sticky bombs are a common threat in Kabul, where militants often stick explosives to the bottom of vehicles.
Kabul police spokesman Faramarz Firdaws said a second bomb was defused near the explosion site.
No group has so far claimed responsibility for the attack.
The incident took place just hours after Taliban militants killed at least 12 and injured over 80 when they set off two car bombs outside the police headquarters in the city of Kandahar in southern Afghanistan on Thursday.
Iran condemns blasts
Later on Friday, Iran’s Foreign Ministry spokesman condemned the terrorist attacks on the police headquarters in Kandahar and the Kabul University.
Seyyed Abbas Mousavi also expressed sympathy with Afghanistan’s government and people, especially the families of the victims.
He expressed confidence that the Afghan government and people “and all the ethnic, political, and religious groups in the country… will continue on the path to restore peace and security in Afghanistan.”
The US and its allies invaded Afghanistan in 2001. While the invasion ended the Taliban’s rule in the country, it has failed to eliminate the militant group. Some 18 years on, Washington is seeking truce with the militants as they have boosted their campaign of violence across the country.
The Daesh terrorist group has also emerged in the Asian country more recently.