WebExtensions can bypass user prompts to first save and then open an arbitrarily downloaded file. This can result in an executable file running with local user privileges without explicit user consent. This vulnerability affects Firefox < 58.
http://www.securityfocus.com/bid/102786
http://www.securitytracker.com/id/1040270
https://bugzilla.mozilla.org/show_bug.cgi?id=1390882
Source: MITRE
Published: 2018-06-11
Updated: 2019-10-03
Type: NVD-CWE-noinfo
Base Score: 7.2
Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C
Impact Score: 10
Exploitability Score: 3.9
Severity: HIGH
Base Score: 7.8
Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 1.8
Severity: HIGH