The public and political anger at the apparent double-standards has put Johnson's position in jeopardy, prompting speculation he could be ousted or have to resign.
But doubts about Johnson's immediate future have subsided after London's Metropolitan Police announced last week detectives had begun their own probe into the events.
The Cabinet Office issued a carefully worded statement indicating Gray had submitted a redacted version of her report to Downing Street.
"We can confirm that Sue Gray has provided an update on her investigations to the prime minister," it read.
The Met last week ordered her not to publish the report in full, so as not to prejudice their investigations, giving Johnson breathing space while detectives conduct enquiries.
Johnson's political opponents have accused him of misleading parliament by insisting the events at Downing Street were within the rules at the time and were work-related.
Ministers found to have done so are normally under pressure to resign but on a visit on Monday, Johnson told reporters: "I stick absolutely to what I've said in the past."
Johnson has previously promised to make a statement to MPs in the House of Commons once he has received the report.