Constructing audio sinks could have lead to a race condition when playing audio files and closing windows. This could have lead to a use-after-free 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/