CVE-2019-11757
When following the value’s prototype chain, it was possible to retain a reference to a locale, delete it, and subsequently reference it. This resulted in a use-after-free and a potentially exploitable crash. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2. Date published : 2020-01-08 https://bugzilla.mozilla.org/show_bug.cgi?id=1577107