Mozilla Thunderbird is a standalone mail and newsgroup client. This update upgrades Thunderbird to version 68.3.0. Security Fix: * Mozilla: Use-after-free in worker destruction * Mozilla: Memory safety bugs fixed in Firefox 71 and Firefox ESR 68.3 * Mozilla: Buffer overflow in plain text serializer * Mozilla: Use-after-free when performing device orientation checks * Mozilla: Use-after-free when retrieving a document in antitracking 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.