CVE 2018-12365
A compromised IPC child process can escape the content sandbox and list the names of arbitrary files on the file system without user consent or interaction. This could result in exposure of private local files. This vulnerability affects Thunderbird < 60, Thunderbird < 52.9, Firefox ESR < 60.1, Firefox ESR < 52.9, and Firefox < 61.
See the 
CVE page on Mitre.org
for more details.
