CVE-2017-7764

Characters from the “Canadian Syllabics” unicode block can be mixed with
characters from other unicode blocks in the addressbar instead of being
rendered as their raw “punycode” form, allowing for domain name spoofing
attacks through character confusion. The current Unicode standard allows
characters from “Aspirational Use Scripts” such as Canadian Syllabics to be
mixed with Latin characters in the “moderately restrictive” IDN profile. We
have changed Firefox behavior to match the upcoming Unicode version 10.0
which removes this category and treats them as “Limited Use Scripts.”. This
vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird <
52.2.