CVE-2018-5163
Mozilla: Replacing cached data in JavaScript Start-up Bytecode Cache
Severity
ModerateRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · May 9, 2018
Updated · November 22, 2025
Description
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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 8.1CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE-829 · Inclusion of Functionality from Untrusted Control Sphere