CINCINNATI  All five voting systems used in Ohio, a state whose electoral votes narrowly swung two elections toward President Bush, have critical flaws that could undermine the integrity of the 2008 general election, a report commissioned by the state’s top elections official has found.

“It was worse than I anticipated,” the official, Secretary of State Jennifer Brunner, said of the report. “I had hoped that perhaps one system would test superior to the others.”

At polling stations, teams working on the study were able to pick locks to access memory cards and use hand-held devices to plug false vote counts into machines. At boards of election, they were able to introduce malignant software into servers.

Ms. Brunner proposed replacing all of the state’s voting machines, including the touch-screen ones used in more than 50 of Ohio’s 88 counties. She wants all counties to use optical scan machines that read and electronically record paper ballots that are filled in manually by voters.