An out-of-bounds read occurs when applying style rules to pseudo-elements, such as ::first-line, using cached style data. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.Referenceshttps://www.mozilla.org/security/advisories/mfsa2017-19/https://www.mozilla.org/security/advisories/mfsa2017-20/https://www.debian.org/security/2017/dsa-3968https://www.mozilla.org/security/advisories/mfsa2017-18/https://access.redhat.com/errata/RHSA-2017:2456https://access.redhat.com/errata/RHSA-2017:2534http://www.securityfocus.com/bid/100315https://bugzilla.mozilla.org/show_bug.cgi?id=1353312http://www.securitytracker.com/id/1039124https://security.gentoo.org/glsa/201803-14https://www.debian.org/security/2017/dsa-3928
