The space agency said although the laptop, stolen from a locked vehicle, has password protection the data had not been encrypted, suggesting skilled hackers could recover the information, The New York Times reported Wednesday.
NASA notified its employees Tuesday of the theft.
"On Oct. 31, 2012, a NASA laptop and official NASA documents issued to a headquarters employee were stolen from the employee's locked vehicle," the agency said in the notification. "The laptop contained records of sensitive personally identifiable information for a large number of NASA employees, contractors and others."
NASA spokeswoman Beth Dickey said the laptop had been scheduled for a security upgrade.
"The laptop was scheduled to receive encryption, as part of an ongoing, agency-wide effort to encrypt whole disks of all NASA computers," she said. "This one just hadn't been done yet."
NASA has said it plans to have hard drives on all of its laptops equipped with encryption software by Dec. 21.