How severe is CVE-2018-12386?

CVE-2018-12386 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2018-12386 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-12386?

CVE-2018-12386 primarily affects Mozilla Firefox. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-12386?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-12386 published?

CVE-2018-12386 was published on 2018-10-18 and last updated on 2026-06-17.

CVE-2018-12386

CVE-2018-12386 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.1. Its EPSS exploit-prediction score of 13% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-704.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 5.8
EPSS exploit prediction: 13% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-704
Affected product: Mozilla Firefox
Published: 2018-10-18
Last modified: 2026-06-17

Description

A vulnerability in register allocation in JavaScript can lead to type confusion, allowing for an arbitrary read and write. This leads to remote code execution inside the sandboxed content process when triggered. This vulnerability affects Firefox ESR < 60.2.2 and Firefox < 62.0.3.

Frequently asked questions

What is CVE-2018-12386?: A vulnerability in register allocation in JavaScript can lead to type confusion, allowing for an arbitrary read and write. This leads to remote code execution inside the sandboxed content process when triggered. This vulnerability affects Firefox ESR < 60.2.2 and Firefox < 62.0.3.
How severe is CVE-2018-12386?: CVE-2018-12386 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2018-12386 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-12386?: CVE-2018-12386 primarily affects Mozilla Firefox. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-12386?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-12386 published?: CVE-2018-12386 was published on 2018-10-18 and last updated on 2026-06-17.

References

Affected products (15)

cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*

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