readAsText() can indefinitely read the file picked by the user, rather than only once at the time the file is picked in File API in Google Chrome prior to 66.0.3359.117 allowed a remote attacker to access data on the user file system without explicit consent via a crafted HTML page.
https://www.debian.org/security/2018/dsa-4182
https://security.gentoo.org/glsa/201804-22
https://chromereleases.googleblog.com/2018/04/stable-channel-update-for-desktop.html