A use-after-free vulnerability can occur when deleting an input element during a mutation event handler triggered by focusing that element

A use-after-free vulnerability can occur when deleting an input element during a mutation event handler triggered by focusing that element. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60, Thunderbird < 52.9, Firefox ESR < 60.1, Firefox ESR < 52.9, and Firefox < 61.