The incident took place on the road from the airport to the Afghan capital and occurred "in close proximity to German Brigadier General Michael Podzus's convoy," the website reported.
A separate Taliban truck bomb on Monday in the same area left dozens injured, according to Afghan officials.
The general, who is in Kabul as part of the NATO-led "Resolute Support" mission to train and advise the Afghan army, was unhurt, Spiegel said, without saying whether the convoy was the intended target of the attack.
The German army said in a brief statement on its website that two soldiers had received minor injuries and an Enok armoured vehicle had been damaged.
"The vehicles were able to continue their journey on their own. The two lightly injured soldiers underwent a medical examination and have received treatment," the army said.
The communique did not say whether a high-ranking general had been travelling with the convoy.
Kabul has been hit by a string of attacks in recent days, while a 25-hour gun and bomb siege near the Indian consulate in the city of Mazar-i-Sharif ended late Monday.