If a malicious attacker has used another vulnerability to gain full control over a content process, they may be able to replace the alternate data resources stored in the JavaScript Start-up Bytecode Cache (JSBC) for other JavaScript code. If the parent process then runs this replaced code, the executed script would be run with the parent process' privileges, escaping the sandbox on content processes. This vulnerability affects Firefox < 60.
http://www.securityfocus.com/bid/104139
http://www.securitytracker.com/id/1040896
https://bugzilla.mozilla.org/show_bug.cgi?id=1426353
Source: MITRE
Published: 2018-06-11
Updated: 2019-10-03
Type: CWE-281
Base Score: 5.1
Vector: AV:N/AC:H/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 4.9
Severity: MEDIUM
Base Score: 8.1
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 2.2
Severity: HIGH