browser/ui/cocoa/browser_window_controller_private.mm in Google Chrome before 53.0.2785.113 does not process fullscreen toggle requests during a fullscreen transition, which allows remote attackers to cause a denial of service (unsuppressed popup) via a crafted web site.
https://security.gentoo.org/glsa/201610-09
https://googlechromereleases.blogspot.com/2016/09/stable-channel-update-for-desktop_13.html
https://codereview.chromium.org/2053343003
http://www.securitytracker.com/id/1036826
http://www.securityfocus.com/bid/92942