net-voip/blink depends on dev-qt/qtwebkit:4 which is ancient and will never see any security updates. If there's no upstream fix available, it might be time to remove this package.
There's a 3.0.3 release which is ported to PyQt5.
commit 33b4ec45a9d7ce56c28ba695f31fcbb048f76abb Author: Michał Górny <mgorny@gentoo.org> AuthorDate: Mon Aug 14 23:18:05 2017 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: Mon Aug 14 23:24:28 2017 net-voip/blink: Remove last-rited pkg, #575772