From the release blog:
This update includes 2 security fixes. Below, we highlight fixes that were contributed by external researchers. Please see the Chrome Security Page for more information.
[$7500] High CVE-2017-15429: UXSS in V8. Reported by Anonymous on 2017-11-24.
Maintainer(s), please cleanup.
Added to existing GLSA request.
@Security, please add bug ID to CVETool, thank you.
Gentoo Security Padawan
This issue was resolved and addressed in
GLSA 201801-03 at https://security.gentoo.org/glsa/201801-03
by GLSA coordinator Aaron Bauman (b-man).