CVE-2021-38500
Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 78.15, Thunderbird < 91.2, Firefox ESR < 91.2, Firefox ESR < 78.15, and Firefox < 93.
Source: CVE-2021-38500