A use-after-free can occur when events are fired for a "FontFace" object after the object has been already been destroyed while working with fonts. This results in a potentially exploitable crash. This vulnerability affects Firefox < 52, Firefox ESR < 45.8, Thunderbird < 52, and Thunderbird < 45.8.
http://rhn.redhat.com/errata/RHSA-2017-0459.html
http://rhn.redhat.com/errata/RHSA-2017-0461.html
http://rhn.redhat.com/errata/RHSA-2017-0498.html
http://www.securityfocus.com/bid/96664
http://www.securitytracker.com/id/1037966
https://bugzilla.mozilla.org/show_bug.cgi?id=1334876
https://security.gentoo.org/glsa/201705-06
https://security.gentoo.org/glsa/201705-07
https://www.debian.org/security/2017/dsa-3805
https://www.debian.org/security/2017/dsa-3832
https://www.mozilla.org/security/advisories/mfsa2017-05/
https://www.mozilla.org/security/advisories/mfsa2017-06/
Source: MITRE
Published: 2018-06-11
Updated: 2018-08-07
Type: CWE-416
Base Score: 7.5
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 10
Severity: HIGH
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 3.9
Severity: CRITICAL