An issue was discovered in certain Apple products. iOS before 11.3 is affected. Safari before 11.1 is affected. iCloud before 7.4 on Windows is affected. iTunes before 12.7.4 on Windows is affected. watchOS before 4.3 is affected. The issue involves the fetch API in the "WebKit" component. It allows remote attackers to bypass the Same Origin Policy and obtain sensitive information via a crafted web site.
https://www.debian.org/security/2018/dsa-4256
https://usn.ubuntu.com/3635-1/
https://support.apple.com/HT208697
https://support.apple.com/HT208696
https://support.apple.com/HT208695
https://support.apple.com/HT208694
https://support.apple.com/HT208693
https://security.gentoo.org/glsa/201808-04
https://security.gentoo.org/glsa/201808-01
https://access.redhat.com/errata/RHSA-2018:2282