The 37-year-old aide and envoy - who is married to Ivanka Trump - lost his top-level security clearance amid a broader White House shakeup in February, restricting his access to America's most closely guarded secrets.
The New York Times has confirmed that the Federal Bureau of Investigation has concluded their background check into President Donald Trump's son-in-law and policy adviser.
His temporary clearance was suspended by White House Chief of Staff John Kelly in February along with other officials operating under temporary clearances as part of measures to tighten procedures after White House staff secretary Rob Porter was sacked when his two ex-wives raised charges of domestic abuse.
Kushner's lawyer said he has been cooperative with all congressional probes and Mueller's office.
"With respect to the news about his clearances, as we stated before, his application was properly submitted, reviewed by numerous career officials and underwent the normal process", Lowell told the newspaper.
Lowell continued to sidestep the question of whether Kushner was a target, subject, or witness, saying, "Nobody has indicated they have any intention of saying to him, you've done something wrong that would merit any charges".More news: House conservatives want second special counsel to investigate alleged DOJ 'misconduct'
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Kushner's access was downgraded in February when White House Chief of Staff John Kelly ordered that officials with interim clearances be cut off if they hadn't received permanent clearances.
Kushner is leading a Trump effort to resurrect the Israeli-Palestinian peace process and has been a Trump conduit to Mexico, among other activities.
After it became clear that Kushner had actually met with many foreign officials during the presidential campaign, however, he amended his form to reflect more than 100 contacts. Kushner, President Donald Trump's son-in-law, has been granted permanent security clearance.
The wealthy NY real estate developer had to refile the national security questionnaire required of all prospective White House employees after making a number of omissions.
Kushner's security clearance reinstatement comes after a second meeting he had with Mueller in April, in which he answered questions for seven hours.
Some experts said that the evolving disclosures might have been disqualifying for another person and that it could explain the delay in granting Kushner a clearance.