Paul Manafort, Campaign Manager for Donald Trump, speaks on the phone while touring the floor of the Republican National Convention at the Quicken Loans Arena as final preparations continue July 17, 2016 in Cleveland, Ohio.

Special counsel Robert Mueller has accused former Trump campaign chief Paul Manafort of lying about sharing polling data with an alleged Russian spy during the 2016 presidential campaign, a new court filing by Manafort's criminal defense lawyers has accidentally revealed.

The alleged spy, Konstantin Kilimnik, is a former business associate of Manafort's who is criminally charged with working with him to try to tamper with potential witnesses against Manafort before his scheduled federal criminal trials last summer.

Mueller has previously alleged that Kilimnik has "ties to a Russian intelligence service and had such ties in 2016," the same year during which Manafort acted as chairman of President Donald Trump's campaign.

The defense filing also reveals that Mueller has accused Manafort of lying to Mueller about a text message from "a third-party asking permission to use Mr. Manafort's name as an introduction in the event the third-party met the President."

Manafort's lawyers meant for those accusations by Mueller, and several others, to be sealed from public view. The sections containing the accusations are blacked out in an otherwise public document filed Tuesday in federal court in Washington, D.C.

But those sections are easily viewable when the sections are copied in a word processing file, and then pasted into a new document.

Defense lawyers filed a "corrected" version of the document later Tuesday, making the redactions unviewable.

The White House, Trump's campaign and Manafort's defense lawyers did not immediately respond to CNBC's requests for comment on the filing.

Manafort is being held without bail as he awaits sentencing for crimes related to his work for a pro-Russia political party in Ukraine, and to income earned from that work. The crimes predated his tenure with the Trump campaign.

The defense filing was responding to Mueller's allegations this past fall that Manafort has violated his cooperation agreement with the special counsel's office by lying to investigators.

Manafort signed that agreement last summer when he pleaded guilty on the eve of a trial in Washington, a month after being convicted in a federal trial for a related case in Virginia.