CVE-2021-43535
A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 93, Thunderbird < 91.3, and Firefox ESR < 91.3. Date published : 2021-12-08 https://bugzilla.mozilla.org/show_bug.cgi?id=1667102