Memory safety bugs were reported in Firefox 58 and Firefox ESR 52.6. 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 < 52.7, Firefox ESR < 52.7, and Firefox < 59.
595952.752.7Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:H8.8/CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H