CVE-2017-5447: Mozilla: Out-of-bounds read during glyph processing (MFSA 2017-11, MFSA 2017-12)

Severity: Critical

CVSS Score: 9.1

An out-of-bounds read during the processing of glyph widths during text layout. This results in a potentially exploitable crash and could allow an attacker to read otherwise inaccessible memory. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.