An inquiry said weak leadership, misuse of resources and lack of coordination between Afghan security services caused fall of Kunduz to Taliban in September.
Amrullah Saleh, head of the investigation team and a former intelligence agency chief, said that “The first biggest failure is leadership."
The team was appointed by Afghan President Ashraf Ghani, for whom the failure was an embarrassment.
A 30 page length summary of the report prepared by Afghan investigators was released on Saturday. The full report was submitted to President Ghani a month ago.
Saleh said that “Weakness in leadership, complexity within structure, and misuse of facilities and resources were the factors” which led Taliban to take control of Kunduz on September 28 for three days.
A government counter-offensive with troop and aircraft support from the United States took the strategic city, which is an important transportation hub for the north of the country, back in two weeks.
Taliban seized 37 armoured vehicles and some 1,000 different types of weapons from the security forces when they had entered Kunduz, Saleh said.
He said he had offered a reform for the National Security Council, which is also at fault.
Saleh said that Taliban militants took their "instructions" from "someone in Peshawar, Pakistan."
Afghanistan's intelligence service recorded telephone conversations between Taliban leaders in Kunduz and unnamed "individuals in the Taliban base of Peshawar," the report says.
He also blamed Pakistani authorities for supporting Taliban in their assault of Kunduz. Afghanistan accuses Pakistan to give a safe zone to Taliban leaders.
Pakistan denies involvement in the Kunduz Assault.
US forces to prolong
NATO’s mission in Afghanistan ended in last December, but the fall of Kunduz, a major success for Taliban since it was overthrown from power in 2001, caused the United States to prolong its military engagement in the country.
President Barack Obama announced a US force of 9,800 will settle in Afghanistan through most of 2016 due to “very fragile” security situation.
Some 200 people including civilians and security officials were killed during the fight, while provincial governor said Taliban fatalities were higher.