A highly classified report sent this month to President Reagan criticizes the CIA and the FBI for "mishandling" the case of former CIA agent Edward Lee Howard, who gave the Soviet Union details of U.S. espionage in Moscow after being fired for erratic behavior, according to sources with knowledge of the document.

Howard's disclosure led the Soviets to apparently execute one of the CIA's prime Moscow contacts and devastated the agency's human intelligence operations in the Soviet capital, the sources said. Howard eluded FBI agents in New Mexico in last year and his location is currently unknown.

The report, by the 11-member President's Foreign Intelligence Advisory Board, has been delivered to Federal Bureau of Investigation and Central Intelligence Agency officials. It is said to single out for criticism the top CIA spymaster's office, the post of deputy director of operations, for overlooking repeated blunders in Howard's hiring, screening and dismissal.

The report charges that agency officials acted irresponsibly in firing Howard. It also accuses the CIA of repeatedly failing to relay concerns about Howard to the FBI, which conducts domestic counterintelligence investigations of suspected security risks. And it criticizes the FBI for foot-dragging and poor police work in its later pursuit of Howard. In addition, it recommends broad changes in CIA hiring, firing and employe-screening procedures.

CIA Director William J. Casey, refused through an agency spokesman to comment on the report or the Howard matter. The FBI also would not comment.

However, one official who spoke on the condition he not be identified, termed the Howard affair "the most graphic foul-up in many years" in internal CIA operations and characterized Casey as "very disturbed about it."

The Howard case was detailed in a May 30 Washington Post report that said Howard was identified as a traitor, along with convicted spy Ronald W. Pelton, by KGB officer Vitaly Yurchenko, who defected to the United States and then returned to the Soviet Union.