CVE 2019-9788

Mozilla developers and community members reported memory safety bugs present in Firefox 65, Firefox ESR 60.5, and Thunderbird 60.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

See the CVE page on Mitre.org for more details.