When inserting text while in edit mode, some characters might have lead to out-of-bounds memory access causing a potentially exploitable crash. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
https://www.mozilla.org/security/advisories/mfsa2022-03/
https://www.mozilla.org/security/advisories/mfsa2022-02/