Mozilla Thunderbird is a standalone mail and newsgroup client. This update upgrades Thunderbird to version 91.2.0. Security Fix: * Mozilla: Use-after-free in MessageTask * Mozilla: Memory safety bugs fixed in Firefox 93, Firefox ESR 78.15, and Firefox ESR 91.2 * Mozilla: Memory safety bugs fixed in Firefox 93 and Firefox ESR 91.2 * Mozilla: Downgrade attack on SMTP STARTTLS connections * rust-crossbeam-deque: race condition may lead to double free * Mozilla: Validation message could have been overlaid on another origin * Mozilla: Use-after-free of nsLanguageAtomService object For more details about the security issue, including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page listed in the References section.