Mozilla Thunderbird is a standalone mail and newsgroup client. This update upgrades Thunderbird to version 78.9.0. Security Fix(es): * Mozilla: Texture upload into an unbound backing buffer resulted in an out-of-bound read (CVE-2021-23981) * Mozilla: Memory safety bugs fixed in Firefox 87 and Firefox ESR 78.9 (CVE-2021-23987) * Mozilla: Internal network hosts could have been probed by a malicious webpage (CVE-2021-23982) * Mozilla: Malicious extensions could have spoofed popup information (CVE-2021-23984) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.