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Fencer Vulns
critical 9.1

CVE-2018-12387 json

A vulnerability where the JavaScript JIT compiler inlines Array.prototype.push with multiple arguments that results in the stack pointer be…

published 2018-10-18 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-4361

cvss
9.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
9.6%
EPSS 9.6% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

A vulnerability where the JavaScript JIT compiler inlines Array.prototype.push with multiple arguments that results in the stack pointer being off by 8 bytes after a bailout. This leaks a memory address to the calling function which can be used as part of an exploit inside the sandboxed content process. This vulnerability affects Firefox ESR < 60.2.2 and Firefox < 62.0.3.

Patch / fix

  • Mozilla Firefox ESR 60.2.2
  • Mozilla Firefox 62.0.3
  • firefox-esr Debian 14, Debian 13, Debian 12 60.2.2esr-1

debian advisories DEBIAN-CVE-2018-12387

  • firefox Ubuntu 14.04 LTS 62.0.3+build1-0ubuntu0.14.04.2
  • firefox Ubuntu 16.04 LTS 62.0.3+build1-0ubuntu0.16.04.2
  • firefox Ubuntu 18.04 LTS 62.0.3+build1-0ubuntu0.18.04.1
  • thunderbird Ubuntu 14.04 LTS 1:60.4.0+build2-0ubuntu0.14.04.1
  • thunderbird Ubuntu 16.04 LTS 1:60.4.0+build2-0ubuntu0.16.04.1
  • thunderbird Ubuntu 18.04 LTS 1:60.4.0+build2-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2018-12387

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox RHEL 6 60.2.2-1.el6
  • firefox RHEL 7 60.2.2-1.el7_5

red hat advisories RHSA-2018:2881RHSA-2018:2884

  • apache2-mod_nss SLES 12 SP4, SLES 12 SP3, OpenStack Cloud 7 +7 more 1.0.14-19.6.3
  • mozilla-nss SLES 12 SP4, SLES 12 SP3, SLED 12 SP4 +12 more 3.36.4-58.15.3
  • mozilla-nspr SLES 12 SP4, SLES 12 SP3, SLED 12 SP4 +12 more 4.19-19.3.1
  • MozillaFirefox SLES 12 SP4, SLES 12 SP3, SLED 12 SP4 +12 more 60.2.2esr-109.46.1
  • MozillaFirefox-branding-SLE SLES 12 SP4, SLES 12 SP3, SLED 12 SP4 +10 more 60-32.3.1
  • MozillaFirefox SLE Module for Desktop Applications 15 60.2.2-3.13.3
  • MozillaFirefox-branding-SLE SLE Module for Desktop Applications 15 60-4.5.3

suse advisories SUSE-SU-2018:3591-2SUSE-SU-2018:3591-1SUSE-SU-2018:3476-1

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 92.0-1.2

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1

  • firefox Arch Linux 62.0.3-1

arch linux advisories AVG-775

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-12387 updated cvss 8.8

Mozilla: stack out-of-bounds read in Array.prototype.push

  • Red Hat Enterprise Linux Client (v. 7) firefox 60.2.2-1.el7_5 Red Hat Enterprise Linux Client Optional (v. 7) firefox 60.2.2-1.el7_5
    fixed: vendor fix RHSA-2018:2884
  • Red Hat Enterprise Linux Desktop (v. 6) firefox 60.2.2-1.el6 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 60.2.2-1.el6
    fixed: vendor fix RHSA-2018:2881
  • Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) firefox 60.2.2-1.el7_5
    fixed: vendor fix RHSA-2018:2884
  • Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 60.2.2-1.el6 Red Hat Enterprise Linux Server (v. 6) firefox 60.2.2-1.el6
    fixed: vendor fix RHSA-2018:2881
  • Red Hat Enterprise Linux Server (v. 7) firefox 60.2.2-1.el7_5
    fixed: vendor fix RHSA-2018:2884
  • Red Hat Enterprise Linux Server Optional (v. 6) firefox 60.2.2-1.el6
    fixed: vendor fix RHSA-2018:2881
  • Red Hat Enterprise Linux Server Optional (v. 7) firefox 60.2.2-1.el7_5
    fixed: vendor fix RHSA-2018:2884
  • Red Hat Enterprise Linux Workstation (v. 6) firefox 60.2.2-1.el6
    fixed: vendor fix RHSA-2018:2881
show 4 more
  • Red Hat Enterprise Linux Workstation (v. 7) firefox 60.2.2-1.el7_5
    fixed: vendor fix RHSA-2018:2884
  • Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 60.2.2-1.el6
    fixed: vendor fix RHSA-2018:2881
  • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 60.2.2-1.el7_5
    fixed: vendor fix RHSA-2018:2884
  • Red Hat Enterprise Linux 6 thunderbird Red Hat Enterprise Linux 7 thunderbird
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

9.59% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1493903 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 9.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:N/A:P

Affected products

  • Mozilla Firefox ESR
  • Mozilla Firefox

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.