An issue was discovered in certain Apple products. macOS before 10.12.4 is affected. The issue involves the "iBooks" component. It allows remote attackers to obtain sensitive information from local files via a file: URL in an iBooks file.
https://support.apple.com/HT207615
https://s1gnalcha0s.github.io/ibooks/epub/2017/03/27/This-book-reads-you-using-JavaScript.html