CVE 2019-8649
A logic issue existed in the handling of synchronous page loads. This issue was addressed with improved state management. This issue is fixed in iOS 12.4, macOS Mojave 10.14.6, tvOS 12.4, Safari 12.1.2, iTunes for Windows 12.9.6, iCloud for Windows 7.13, iCloud for Windows 10.6. Processing maliciously crafted web content may lead to universal cross site scripting.
See the 
CVE page on Mitre.org
for more details.
