The implementation of the Page.downloadBehavior backend unconditionally marked downloaded files as safe, regardless of file type in Google Chrome prior to 66.0.3359.117 allowed an attacker who convinced a user to install a malicious extension to potentially perform a sandbox escape via a crafted HTML page and user interaction.
https://access.redhat.com/errata/RHSA-2018:2282
https://chromereleases.googleblog.com/2018/04/stable-channel-update-for-desktop.html