A mechanism to bypass file system access protections in the sandbox to use the file picker to access different files than those selected in the file picker through the use of relative paths. This allows for read only access to the local file system. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.
http://www.securityfocus.com/bid/97940
http://www.securitytracker.com/id/1038320
https://access.redhat.com/errata/RHSA-2017:1106
https://access.redhat.com/errata/RHSA-2017:1201
https://bugzilla.mozilla.org/show_bug.cgi?id=1349276
https://www.mozilla.org/security/advisories/mfsa2017-10/
Source: MITRE
Published: 2018-06-11
Updated: 2018-08-09
Type: CWE-200
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: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH