The IRS has announced - and news media have reported - that hackers penetrated the Get Transcript System, using personal information already in their possession.
The purpose seem to be to use the transcript data to file fraudulent tax returns.
The IRS will notify taxpayers if their data has been compromised.
It is important to note that, according to the IRS, the e-filing system was not compromised and remains secure.
(The Get Transcript app is on a separate server system.)
The above information was excerpted from the Journal of Accountancy article at:
http://www.journalofaccountancy.com/news/2015/may/irs-get-transcript-app-hack-201512393.html
Update: The number of accounts compromised is now over 300,000.
"Stay tuned for further developments."