Even before being approached by a reporter, Ms. Spanberger said in the interview that she had become suspicious that the application had been leaked because Republican-aligned groups conducting “push polling” in the race had been asking respondents whether they knew she had once taught at the Islamic Saudi Academy in Alexandria, Va., an international baccalaureate program.

One of her supporters received a call from the polling company and reported that she was asked if she would be less likely to support Ms. Spanberger if she knew that the candidate had taught at a school funded by the Saudi royal family that had “numerous students arrested for terrorism,” Ms. Spanberger said.

A recent graduate from the University of Virginia at the time, Ms. Spanberger returned to the United States in 2002 after teaching in Germany and earning a master’s degree. She applied for a job at the C.I.A. that year and was told in December that she had a conditional offer pending her background check, which she was told could take at least six months.

She waited tables in the interim, and a colleague asked her if she would be interested in a temporary job teaching English at the academy to cover for another instructor’s maternity leave, Ms. Spanberger said.

As she awaited final word from the C.I.A., she took a job at the Postal Inspection Service, the law enforcement arm of the Postal Service. She said she filled out the federal forms for both jobs at about the same time. She also said she informed the C.I.A. each time she took on new employment.

National security experts said that the unauthorized release of such a highly confidential document is particularly troubling if it turns out to not be an isolated episode.

“It calls for a tremendous amount of extremely private, personal information, and so to the person whose information is at stake, it is extremely significant,” said David Kris, a founder of Culper Partners and a former assistant attorney general for national security.