When adding a range to an object in the DOM, it is possible to use "addRange" to add the range to an incorrect root object. This triggers a use-after-free, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 52 and Thunderbird < 52.
https://www.mozilla.org/security/advisories/mfsa2017-09/
https://www.mozilla.org/security/advisories/mfsa2017-05/
https://bugzilla.mozilla.org/show_bug.cgi?id=1340186