An integer overflow vulnerability in the Skia library when allocating memory for edge builders on some systems with at least 16 GB of RAM.

published 2020-07-09 6 y ago modified 2026-06-17 4 mo ago also EUVD-2018-4345

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.4%; EPSS 1.4% chance of exploitation in 30 days, percentile 73%
public exploits: 0; none known

An integer overflow vulnerability in the Skia library when allocating memory for edge builders on some systems with at least 16 GB of RAM. This results in the use of uninitialized memory, resulting in a potentially exploitable crash. This vulnerability affects Firefox ESR < 60.1, Thunderbird < 60, and Firefox < 61.

Patch / fix

fixed in 3 distros 5 links 1

Mozilla Firefox ESR 60.1
Mozilla Thunderbird 60
Mozilla Firefox 61

debian ubuntu suse opensuse arch linux

thunderbird Debian 14, Debian 13, Debian 12 1:60.0-1

debian advisories DEBIAN-CVE-2018-12371

firefox Ubuntu 14.04 LTS 61.0+build3-0ubuntu0.14.04.2
firefox Ubuntu 16.04 LTS 61.0+build3-0ubuntu0.16.04.2
firefox Ubuntu 18.04 LTS 61.0+build3-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2018-12371

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

MozillaThunderbird SLE Workstation Extension 15 60.2.1-3.13.1

suse advisories SUSE-SU-2018:3247-1

firefox-esr openSUSE Tumbleweed 128.5.1-1.1
MozillaFirefox openSUSE Tumbleweed 92.0-1.2
MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
MozillaThunderbird Package Hub 12 60.3.0-74.2

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1 openSUSE-SU-2024:10601-1 openSUSE-SU-2018:3687-1

firefox Arch Linux 61.0-1
thunderbird Arch Linux 60.0-1

arch linux advisories AVG-727 AVG-751

bugzilla.mozilla.org/show_bug.cgi?id=1465686 advisory

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-2018-12371 updated 2026-11-05 cvss 8.8

Mozilla: Integer overflow in Skia library during edge builder allocation

Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 firefox, 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

1.45% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1465686 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD	2.0	6.8	AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

Mozilla Firefox ESR
Mozilla Thunderbird
Mozilla Firefox

Classification

Weakness

CWE-190 Integer Overflow or Wraparound

References

bugzilla.mozilla.org /show_bug.cgi?id=1465686
exploit, issue-tracking, patch, vendor-advisory
mozilla.org /security/advisories/mfsa2018-16/
vendor-advisory
mozilla.org /security/advisories/mfsa2018-15/
vendor-advisory
mozilla.org /security/advisories/mfsa2018-19/
vendor-advisory

Sources

CVE List CVE-2018-12371
NVD CVE-2018-12371

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.

Summary