CVE-2018-18500

A use-after-free vulnerability can occur while parsing an HTML5 stream in concert with custom HTML elements. This results in the stream parser object being freed while still in use, leading to a potentially exploitable crash. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65. Date published : 2019-02-05 http://www.securityfocus.com/bid/106781

https://www.mozilla.org/security/advisories/mfsa2019-01/