Lack of special casing of localhost in WPAD files in Google Chrome prior to 71.0.3578.80 allowed an attacker on the local network segment to proxy resources on localhost via a crafted WPAD file.
https://www.debian.org/security/2018/dsa-4352
https://security.gentoo.org/glsa/201908-18
https://chromereleases.googleblog.com/2018/12/stable-channel-update-for-desktop.html