CVE-2020-26959
During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5. Date published : 2020-12-08 https://www.mozilla.org/security/advisories/mfsa2020-50/