high 8.8

CVE-2019-9813 json

Incorrect handling of proto mutations may lead to type confusion in IonMonkey JIT code and can be leveraged for arbitrary memory read a…

published 2019-04-26 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-19175

cvss: 8.8; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 6.7%; EPSS 6.7% chance of exploitation in 30 days, percentile 94%
public exploits: 1; Exploit-DB

Incorrect handling of __proto__ mutations may lead to type confusion in IonMonkey JIT code and can be leveraged for arbitrary memory read and write. This vulnerability affects Firefox < 66.0.1, Firefox ESR < 60.6.1, and Thunderbird < 60.6.1.

Patch / fix

fixed in 3 distros 7

Mozilla Firefox 66.0.1
Mozilla Firefox ESR 60.6.1
Mozilla Thunderbird 60.6.1

debian ubuntu red hat suse opensuse alpine arch linux

firefox-esr Debian 14, Debian 13, Debian 12 60.6.1esr-1

debian advisories DEBIAN-CVE-2019-9813

firefox Ubuntu 14.04 LTS 66.0.1+build1-0ubuntu0.14.04.1
firefox Ubuntu 16.04 LTS 66.0.1+build1-0ubuntu0.16.04.1
firefox Ubuntu 18.04 LTS 66.0.1+build1-0ubuntu0.18.04.1
thunderbird Ubuntu 14.04 LTS 1:60.6.1+build2-0ubuntu0.14.04.1
thunderbird Ubuntu 16.04 LTS 1:60.6.1+build2-0ubuntu0.16.04.1
thunderbird Ubuntu 18.04 LTS 1:60.6.1+build2-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2019-9813

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 8 60.6.1-1.el8
firefox RHEL 7 60.6.1-1.el7_6
firefox RHEL 6 60.6.1-1.el6_10
thunderbird RHEL 7 60.6.1-1.el7_6
firefox RHEL 8 60.6.1-1.el8
thunderbird RHEL 6 60.6.1-1.el6_10

red hat advisories RHSA-2019:1144 RHSA-2019:0671 RHSA-2019:0672 RHSA-2019:0681 RHSA-2019:0966 RHSA-2019:0680

MozillaFirefox SLE Module for Desktop Applications 15 60.6.1-3.29.3
MozillaThunderbird SLE Workstation Extension 15 60.6.1-3.28.1
MozillaFirefox SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES for SAP 12 SP2 +13 more 60.6.1esr-109.63.2

suse advisories SUSE-SU-2019:0871-1 SUSE-SU-2019:0853-1 SUSE-SU-2019:0852-1

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 60.6.1-lp150.3.37.1
MozillaThunderbird Package Hub 12 60.6.1-82.1
MozillaFirefox openSUSE Leap 15.0 60.6.1-lp150.3.45.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1 openSUSE-SU-2024:10601-1 openSUSE-SU-2019:1162-1 openSUSE-SU-2019:1126-1 openSUSE-SU-2019:1077-1

firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +12 more 60.6.1-r0

alpine advisories ALPINE-CVE-2019-9813

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

firefox Arch Linux 66.0.1-1
thunderbird Arch Linux 60.6.1-1

arch linux advisories AVG-930 AVG-947

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-2019-9813 updated 2026-11-04 cvss 8.8

Mozilla: Ionmonkey type confusion with __proto__ mutations

Red Hat Enterprise Linux AppStream (v. 8) firefox 60.6.1-1.el8, thunderbird 60.6.1-1.el8
fixed: vendor fix RHSA-2019:0966
Red Hat Enterprise Linux Client (v. 7) firefox 60.6.1-1.el7_6, thunderbird 60.6.1-1.el7_6 Red Hat Enterprise Linux Client Optional (v. 7) firefox 60.6.1-1.el7_6
fixed: vendor fix RHSA-2019:0671
Red Hat Enterprise Linux Desktop (v. 6) firefox 60.6.1-1.el6_10, thunderbird 60.6.1-1.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 60.6.1-1.el6_10
fixed: vendor fix RHSA-2019:0672
Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) firefox 60.6.1-1.el7_6
fixed: vendor fix RHSA-2019:0671
Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) thunderbird 60.6.1-1.el7_6
fixed: vendor fix RHSA-2019:0681
Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 60.6.1-1.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 60.6.1-1.el6_10
fixed: vendor fix RHSA-2019:0672
Red Hat Enterprise Linux Server (v. 7) firefox 60.6.1-1.el7_6
fixed: vendor fix RHSA-2019:0671
Red Hat Enterprise Linux Server Optional (v. 6) firefox 60.6.1-1.el6_10, thunderbird 60.6.1-1.el6_10
fixed: vendor fix RHSA-2019:0672

show 5 more

Red Hat Enterprise Linux Server Optional (v. 7) firefox 60.6.1-1.el7_6, thunderbird 60.6.1-1.el7_6
fixed: vendor fix RHSA-2019:0671
Red Hat Enterprise Linux Workstation (v. 6) firefox 60.6.1-1.el6_10, thunderbird 60.6.1-1.el6_10
fixed: vendor fix RHSA-2019:0672
Red Hat Enterprise Linux Workstation (v. 7) firefox 60.6.1-1.el7_6, thunderbird 60.6.1-1.el7_6
fixed: vendor fix RHSA-2019:0671
Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 60.6.1-1.el6_10
fixed: vendor fix RHSA-2019:0672
Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 60.6.1-1.el7_6
fixed: vendor fix RHSA-2019:0671

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

Timeline

2019-04-03 First public exploit (EDB-46646)
2019-04-26 Published

Exploit prediction

6.75% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

EDB-46646 SpiderMonkey - IonMonkey Compiled Code Fails to Update Inferred Property Types (Type Confusion) dos, 2019-04-03

CVSS scores

assigned by	version	score	vector
NVD	3.0	8.8	CVSS:3.0/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 Firefox ESR
Mozilla Thunderbird

Classification

Weakness

CWE-843 Access of Resource Using Incompatible Type

References

access.redhat.com /errata/RHSA-2019:0966
vendor-advisory
access.redhat.com /errata/RHSA-2019:1144
vendor-advisory
mozilla.org /security/advisories/mfsa2019-09/
vendor-advisory
mozilla.org /security/advisories/mfsa2019-10/
vendor-advisory
mozilla.org /security/advisories/mfsa2019-12/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=1538006
issue-tracking, permissions-required, vendor-advisory

Sources

CVE List CVE-2019-9813
NVD CVE-2019-9813

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