WASHINGTON — Authorized hackers were quickly able to seize control of weapons systems being acquired by the American military in a test of the Pentagon’s digital vulnerabilities, according to a new and blistering government review.

The report by the Government Accountability Office concluded that many of the weapons, or the systems that control them, could be neutralized within hours. In many cases, the military teams developing or testing the systems were oblivious to the hacking.

A public version of the study, published on Tuesday, deleted all names and descriptions of which systems were attacked so the report could be published without tipping off American adversaries about the vulnerabilities. Congress is receiving the classified version of the report, which specifies which among the $1.6 trillion in weapons systems that the Pentagon is acquiring from defense contractors were affected.

But even the declassified review painted a terrifying picture of weaknesses in a range of emerging weapons, from new generations of missiles and aircraft to prototypes of new delivery systems for nuclear weapons.