SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-5163

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.

HIGH 8.1EPSS 2.09%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (2.09%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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 3.0
8.1 HIGHCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
2.09% probability · 81th percentile
CISA KEV
Not listed
Weakness
CWE-281
Affected
canonical/ubuntu linux · mozilla/firefox
Source
security@mozilla.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.