Several fonts on OS X display some Tibetan and Arabic characters as whitespace. When used in the addressbar as part of an IDN this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.
http://www.securityfocus.com/bid/101059
http://www.securitytracker.com/id/1039465
https://bugzilla.mozilla.org/show_bug.cgi?id=1390980
https://bugzilla.mozilla.org/show_bug.cgi?id=1393624
https://lists.debian.org/debian-lts-announce/2017/11/msg00000.html
https://security.gentoo.org/glsa/201803-14
https://www.mozilla.org/security/advisories/mfsa2017-21/
Source: MITRE
Published: 2018-06-11
Updated: 2018-08-06
Type: CWE-20
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 5.3
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Impact Score: 1.4
Exploitability Score: 3.9
Severity: MEDIUM