If you're interested in cross origin information leaks and defenses against them (including Cross Origin Read Blocking), I highly recommend this short 7 page summary by Artur Janc and Mike West from Google:<p><a href="https://www.arturjanc.com/cross-origin-infoleaks.pdf" rel="nofollow">https://www.arturjanc.com/cross-origin-infoleaks.pdf</a>