If a crafted hyperlink is dragged and dropped to the bookmark bar or sidebar and the resulting bookmark is subsequently dragged and dropped into the web content area, an arbitrary query of a user's browser history can be run and transmitted to the content page via drop event data. This allows for the theft of browser history by a malicious site. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.
https://www.mozilla.org/security/advisories/mfsa2019-15/
https://www.mozilla.org/security/advisories/mfsa2019-14/