CVE-2018-5163
HIGHEPSS 81th pctlDescription
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.
How to fix
This Ubuntu release reached end-of-life on 2019-04-02.
This Ubuntu release reached end-of-life on 2021-04-02.
This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Elevated risk: more likely to be exploited than 81% of all known CVEs.
References
Related Vulnerabilities
Other CWE-281 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2017-8543 | Critical | 9.8 | 74% | KEV | - |
| CVE-2019-0233 | High | 7.5 | 68% | - | - |
| CVE-2017-8589 | Critical | 9.8 | 26% | - | - |
| CVE-2021-33990 | Critical | 9.8 | 12% | - | - |
| CVE-2017-8563 | High | 8.1 | 7.2% | - | - |
| CVE-2017-8578 | High | 7.8 | 6.5% | - | - |
Common questions
How do I fix CVE-2018-5163?
Published advisories record a fix for 4 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2018-5163 being actively exploited?
Not that we know of. CVE-2018-5163 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 2.1% is the estimated probability that it will be exploited in the next 30 days. That is higher than 81% of all scored CVEs.
How severe is CVE-2018-5163?
CVE-2018-5163 has a CVSS v3 base score of 8.1, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2018-5163 affect?
Published advisories record a fix for firefox (Debian), firefox (Ubuntu), Firefox Developer Edition (en-US) (Windows application), Mozilla Firefox (en-US) (Windows application). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.