Content Security Policy combined with HTTP to HTTPS redirection can be used by malicious server to verify whether a known site is within a user's browser history. This vulnerability affects Firefox < 50.
http://www.securityfocus.com/bid/94337
http://www.securitytracker.com/id/1037298
Source: MITRE
Published: 2018-06-11
Updated: 2018-07-30
Type: CWE-254
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 5.3
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Impact Score: 1.4
Exploitability Score: 3.9
Severity: MEDIUM