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Public proof of conceptFix available

CVE-2018-12386

A public proof of concept exists; no exploitation attested.

  • Published2018-10-18
  • WeaknessCWE-704

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2018-10-1813:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-04 09:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2018-12386?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2018-12386?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Canonical ubuntu linux
BranchAffectedFixed in
14.4= 14.04no fix published
16.4= 16.04no fix published
18.4= 18.04no fix published
Mozilla firefox
BranchAffectedFixed in
62.0< 62.0.362.0.3
60.2< 60.2.260.2.2
Redhat enterprise linux desktop
BranchAffectedFixed in
6.0= 6.0no fix published
7.0= 7.0no fix published

6 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • apache2-mod_nssSUSE:OpenStack Cloud 7all versions · fixed in 1.0.14-19.6.3
  • apache2-mod_nssSUSE:Linux Enterprise Server for SAP Applications 12 SP4all versions · fixed in 1.0.14-19.6.3
  • apache2-mod_nssSUSE:Linux Enterprise Server for SAP Applications 12 SP3all versions · fixed in 1.0.14-19.6.3
  • apache2-mod_nssSUSE:Linux Enterprise Server for SAP Applications 12 SP2all versions · fixed in 1.0.14-19.6.3
  • apache2-mod_nssSUSE:Linux Enterprise Server for SAP Applications 12 SP1all versions · fixed in 1.0.14-19.6.3
  • apache2-mod_nssSUSE:Linux Enterprise Server 12 SP4all versions · fixed in 1.0.14-19.6.3
  • apache2-mod_nssSUSE:Linux Enterprise Server 12 SP3all versions · fixed in 1.0.14-19.6.3
  • apache2-mod_nssSUSE:Linux Enterprise Server 12 SP2-LTSSall versions · fixed in 1.0.14-19.6.3

84 more package ranges on OSV.dev

Vendor advisories

  • CVE-2018-12386 Red Hat Product Security58 products fixed

    Mozilla: type confusion in JavaScript

  • RHSA-2018:2884 Red Hat Product Security28 products fixed

    Red Hat Security Advisory: firefox security update

  • RHSA-2018:2881 Red Hat Product Security30 products fixed

    Red Hat Security Advisory: firefox security update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2018:2884 · 28 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 After installing the update, Firefox must be restarted for the changes to take effect.

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
2 repositories, unverifiedHydra3evil/cve-2018-123860xLyte/cve-2018-12386
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.08.1read 2026-10-23
  • NVDCVSS 2.05.8read 2026-10-23
  • NVDweakness (CWE)CWE-704read 2026-10-23
  • FIRST EPSSEPSS score13.5 %read 2026-11-03
  • PoC-in-GitHubproof of concept2read 2026-11-03
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Published
2018-10-18
Last Modified
2026-06-17
NVD status
Modified

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.

Is CVE-2018-12386 actively exploited?

Active exploitation of CVE-2018-12386 has not been confirmed. Its EPSS score was 13.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-12386?

CVE-2018-12386 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

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