high 8.8

CVE-2019-11764 json

Mozilla developers and community members reported memory safety bugs present in Firefox 69 and Firefox ESR 68.1.

published 2020-01-08 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-3434

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.5%; EPSS 1.5% chance of exploitation in 30 days, percentile 73%
public exploits: 0; none known

Mozilla developers and community members reported memory safety bugs present in Firefox 69 and Firefox ESR 68.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.

Patch / fix

fixed in 3 distros 7

mozilla firefox 70.0
mozilla firefox_esr 68.2
mozilla thunderbird 68.2

debian ubuntu red hat suse opensuse alpine arch linux

firefox-esr Debian 14, Debian 13, Debian 12 68.2.0esr-1
thunderbird Debian 14, Debian 13, Debian 12 1:68.2.1-1

debian advisories DEBIAN-CVE-2019-11764

firefox Ubuntu 16.04 LTS 70.0+build2-0ubuntu0.16.04.1
firefox Ubuntu 18.04 LTS 70.0+build2-0ubuntu0.18.04.1
firefox Ubuntu 20.04 LTS 70.0+build2-0ubuntu1
thunderbird Ubuntu 16.04 LTS 1:68.7.0+build1-0ubuntu0.16.04.2
thunderbird Ubuntu 18.04 LTS 1:68.2.1+build1-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2019-11764

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

thunderbird RHEL 6 68.2.0-2.el6_10
firefox RHEL 6 68.2.0-4.el6_10
thunderbird RHEL 7 68.2.0-1.el7_7
thunderbird RHEL 8 68.2.0-1.el8_0
firefox RHEL 7 68.2.0-1.el7_7
firefox RHEL 8 68.2.0-2.el8_0

red hat advisories RHSA-2019:3756 RHSA-2019:3281 RHSA-2019:3210 RHSA-2019:3237 RHSA-2019:3193 RHSA-2019:3196

MozillaThunderbird SLE Workstation Extension 15 SP1, SLE Workstation Extension 15 68.2.1-3.58.1
MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +17 more 68.2.0-109.95.2
MozillaFirefox-branding-SLE SLE Module for Desktop Applications 15 SP1, SLE Module for Desktop Applications 15 68-4.11.2
MozillaFirefox SLE Module for Desktop Applications 15 SP1, SLE Module for Desktop Applications 15 68.2.0-3.59.1
firefox-atk SLES 11 SP4-LTSS 2.26.1-2.8.4
mozilla-nss SLES 11 SP4-LTSS 3.45-38.9.3
firefox-gtk3 SLES 11 SP4-LTSS 3.10.9-2.15.3
mozilla-nspr SLES 11 SP4-LTSS 4.21-29.6.1

suse advisories SUSE-SU-2019:14246-1 SUSE-SU-2019:2912-1 SUSE-SU-2019:2872-1 SUSE-SU-2019:2871-1

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 openSUSE Leap 15.0 68.2.1-lp150.3.54.1
MozillaFirefox openSUSE Leap 15.0 68.2.0-lp150.3.71.1
firefox-esr-branding-openSUSE openSUSE Leap 15.0 68-lp150.3.3.1
MozillaFirefox-branding-openSUSE openSUSE Leap 15.0 68-lp150.3.3.1
MozillaThunderbird openSUSE Leap 15.1 68.2.1-lp151.2.16.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1 openSUSE-SU-2024:10601-1 openSUSE-SU-2019:2464-1 openSUSE-SU-2019:2459-1 openSUSE-SU-2019:2452-1

firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 70.0-r0
librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 70.0-r0
firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +10 more 68.2.0-r0

alpine advisories ALPINE-CVE-2019-11764

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

thunderbird Arch Linux 68.2.0-1
firefox Arch Linux 70.0-1

arch linux advisories AVG-1054 AVG-1055

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-2019-11764 updated 2026-11-04 cvss 8.8

Mozilla: Memory safety bugs fixed in Firefox 70 and Firefox ESR 68.2

Red Hat Enterprise Linux 5 firefox, thunderbird
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux AppStream (v. 8) firefox 68.2.0-2.el8_0, thunderbird 68.2.0-1.el8_0
fixed: vendor fix RHSA-2019:3196
Red Hat Enterprise Linux Client (v. 7) firefox 68.2.0-1.el7_7, thunderbird 68.2.0-1.el7_7 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.2.0-1.el7_7
fixed: vendor fix RHSA-2019:3193
Red Hat Enterprise Linux Desktop (v. 6) firefox 68.2.0-4.el6_10, thunderbird 68.2.0-2.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.2.0-4.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.2.0-4.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.2.0-4.el6_10
fixed: vendor fix RHSA-2019:3281
Red Hat Enterprise Linux Server (v. 7) firefox 68.2.0-1.el7_7
fixed: vendor fix RHSA-2019:3193
Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.2.0-4.el6_10, thunderbird 68.2.0-2.el6_10
fixed: vendor fix RHSA-2019:3281
Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.2.0-1.el7_7, thunderbird 68.2.0-1.el7_7
fixed: vendor fix RHSA-2019:3193
Red Hat Enterprise Linux Workstation (v. 6) firefox 68.2.0-4.el6_10, thunderbird 68.2.0-2.el6_10
fixed: vendor fix RHSA-2019:3281

show 3 more

Red Hat Enterprise Linux Workstation (v. 7) firefox 68.2.0-1.el7_7, thunderbird 68.2.0-1.el7_7
fixed: vendor fix RHSA-2019:3193
Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.2.0-4.el6_10
fixed: vendor fix RHSA-2019:3281
Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.2.0-1.el7_7
fixed: vendor fix RHSA-2019:3193

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

1.47% 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/buglist.cgi?bug_id=1558522%2C1577061%2C1548044%2C1571223%2C1573048%2C1578933%2C1575217%2C1583684%2C1586845%2C1581950%2C1583463%2C1586599 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
Mozilla Thunderbird
Mozilla Firefox ESR

Classification

Weakness

CWE-787 Out-of-bounds Write

References

bugzilla.mozilla.org /buglist.cgi?bug_id=1558522%2C1577061%2C1548044%2C1571223%2C1573048%2C1578933%2C1575217%2C1583684%2C1586845%2C
exploit, issue-tracking, vendor-advisory
security.gentoo.org /glsa/202003-10
vendor-advisory, third-party-advisory
usn.ubuntu.com /4335-1/
vendor-advisory, third-party-advisory
mozilla.org /security/advisories/mfsa2019-35/
vendor-advisory
mozilla.org /security/advisories/mfsa2019-33/
vendor-advisory
mozilla.org /security/advisories/mfsa2019-34/
vendor-advisory

Sources

CVE List CVE-2019-11764
NVD CVE-2019-11764

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