CVE 2017-5020
Google Chrome prior to 56.0.2924.76 for Linux, Windows and Mac, and 56.0.2924.87 for Android, failed to require a user gesture for powerful download operations, which allowed a remote attacker who convinced a user to install a malicious extension to execute arbitrary code via a crafted HTML page.
See the 
CVE page on Mitre.org
for more details.
