A use-after-free vulnerability can occur when manipulating elements, events, and selection ranges during editor operations. This results in a potentially exploitable crash. This vulnerability affects Firefox < 59.
https://www.mozilla.org/security/advisories/mfsa2018-06/
https://usn.ubuntu.com/3596-1/
https://bugzilla.mozilla.org/show_bug.cgi?id=1431336