The Canada Revenue Agency confirmed late Tuesday that it has accidentally disclosed confidential taxpayer information to the CBC.
The agency said the document was "accidentally released" through human error and acknowledges this "constitutes a serious breach of privacy."
CBC reported that the tax information contains data about hundreds of Canadians – many of them rich and famous – including their home addresses.
The network said the 18 pages of spreadsheet data includes the value of tax credits they were granted covering the years 2008 to 2013.
Donations made by such high-profile Canadians as author Margaret Atwood, former prime minister Jean Chrétien, grocery magnate Frank Sobey, cartoonist Lynn Johnston, pollster Allan Gregg and others were included.
The CRA said in a release late Tuesday that when it became aware of the breach, officials immediately contacted the CBC to retrieve the documents.
The agency said the CBC "regrettably" chose to disclose names and a response from the network was not immediately available.
However, in its story on the breach, CBC News made clear it was not disclosing much of the information it had. The network said it was "withholding most details from the list, apart from the names of some of the people cited, out of respect for privacy."
The CRA said it has launched an internal investigation into the breach and has contacted the Privacy Commissioner of Canada.
The agency also said it would contact the people affected to advise them of their right to complain to the Privacy Commissioner.
"The CRA shares the concern and dismay of those individuals whose privacy has been impacted and sincerely regrets this error," said the statement from CRA commissioner Andrew Treusch.
The CBC said the information delivered to it in digital format was a mistaken response to a request for other information under the Access to Information Act.