browser/safe_browsing/srt_field_trial_win.cc in Google Chrome before 51.0.2704.63 does not use the HTTPS service on dl.google.com to obtain the Software Removal Tool, which allows remote attackers to spoof the chrome_cleanup_tool.exe (aka CCT) file via a man-in-the-middle attack on an HTTP session.
https://security.gentoo.org/glsa/201607-07
https://codereview.chromium.org/1919043002
https://access.redhat.com/errata/RHSA-2016:1190
http://www.securitytracker.com/id/1035981
http://www.securityfocus.com/bid/90876
http://www.debian.org/security/2016/dsa-3590
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00005.html
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00063.html
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00062.html
http://googlechromereleases.blogspot.com/2016/05/stable-channel-update_25.html