CVE-2018-12368: Mozilla Firefox

High severity, CVSS 8.1. EPSS: 4.8% chance of exploitation in the next 30 days.

Windows 10 does not warn users before opening executable files with the SettingContent-ms extension even when they have been downloaded from the internet and have the "Mark of the Web." Without the warning, unsuspecting users unfamiliar with this new file type might run an unwanted executable. This also allows a WebExtension with the limited downloads.open permission to execute arbitrary code without user interaction on Windows 10 systems. *Note: this issue only affects Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 60, Thunderbird < 52.9, Firefox ESR < 60.1, Firefox ESR < 52.9, and Firefox < 61.

Affected products

• Mozilla Firefox: before 61.0 (fixed in 61.0); from 53.0, before 60.1.0 (fixed in 60.1.0)
• Mozilla Firefox ESR: before 52.9 (fixed in 52.9)
• Mozilla Thunderbird: before 52.9 (fixed in 52.9)

Published 2018-10-18. Last modified 2026-06-17.