COLUMBUS, Ohio – An election-eve lawsuit filed Monday alleges that software in some Ohio voting machines makes the machines vulnerable to having votes altered after they are cast.

The federal lawsuit involving machines made by Omaha, Neb.-based Election Systems and Software alleges that software on the machines could allow vote manipulation by non-election board officials.

A “back door” in ES&S software and hardware creates “an imminent risk” that individuals not supervised by elections boards could “alter the recording and tabulation of votes cast by Ohio voters in the General Election,” according to the lawsuit filed on behalf of Bob Fitrakis, a longtime Ohio elections activist.

The lawsuit asks a judge to order Ohio’s elections chief Jon Husted not to use the machines Tuesday and to break state contracts with ES&S for voting machines to be used this year.

The machines are in Ohio’s 25 most populous counties, said Columbus attorney Cliff Arnebeck, who filed the lawsuit.

A hearing was scheduled for Tuesday morning.

Messages were left with ES&S and Husted’s office seeking comment.

The lawsuit was the second last-minute complaint filed over voting in battleground Ohio. A second federal judge is considering union claims that Husted’s office improperly changed rules for noting the type of identification used on provisional ballots.

The complaint says Husted’s order could lead to provisional ballots being unnecessarily disqualified. Husted’s office said the form in question has already been used twice this year.