Mozilla Thunderbird is a standalone mail and newsgroup client. This update upgrades Thunderbird to version 78.9.1. Security Fix: * Mozilla: An attacker may use Thunderbird"s OpenPGP key refresh mechanism to poison an existing key * Mozilla: A crafted OpenPGP key with an invalid user ID could be used to confuse the user * Mozilla: Inability to send encrypted OpenPGP email after importing a crafted OpenPGP key 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.