Freeing arbitrary <code>nsIInputStream</code>'s on a different thread than creation could have led to a use-after-free and potentially exploitable crash. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.
https://bugzilla.mozilla.org/show_bug.cgi?id=1791314
https://www.mozilla.org/security/advisories/mfsa2022-49/