Incorrect dialog placement in WebContents in Google Chrome prior to 70.0.3538.67 allowed a remote attacker to obscure the full screen warning via a crafted HTML page.
https://www.debian.org/security/2018/dsa-4330
https://security.gentoo.org/glsa/201811-10
https://chromereleases.googleblog.com/2018/10/stable-channel-update-for-desktop.html