Description
Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox ESR | unspecified – < 68.4.1 | 68.4.1 |
| Mozilla | Thunderbird | unspecified – < 68.4.1 | 68.4.1 |
| Mozilla | Firefox | unspecified – < 72.0.1 | 72.0.1 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | firefox-esr | 68.4.1esr-1 | — |
| Debian 14 | thunderbird | 1:68.4.1-1 | — |
| Debian 13 | firefox-esr | 68.4.1esr-1 | — |
| Debian 13 | thunderbird | 1:68.4.1-1 | — |
| Debian 12 | firefox-esr | 68.4.1esr-1 | — |
| Debian 12 | thunderbird | 1:68.4.1-1 | — |
| Debian 10 | firefox-esr | 68.4.1esr-1~deb10u1 | DSA-4600-1 |
| Debian 10 | thunderbird | 1:68.4.1-1~deb10u1 | DSA-4603-1 |
| Debian 9 | firefox-esr | 68.4.1esr-1~deb9u1 | DSA-4600-1 |
| Debian 9 | thunderbird | 1:68.4.1-1~deb9u1 | DSA-4603-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 8 | firefox-esr | 68.4.1esr-1~deb8u1 | DLA-2093-1 |
| Debian 8 | thunderbird | 1:68.4.1-1~deb8u1 | DLA-2071-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | firefox | 72.0.1+build1-0ubuntu1 | — |
| Ubuntu 20.04 LTS | mozjs52 | No fix yet | — |
| Ubuntu 20.04 LTS | thunderbird | 1:68.4.1+build1-0ubuntu1 | — |
| Ubuntu 18.04 LTS | firefox | 72.0.1+build1-0ubuntu0.18.04.1 | USN-4234-1 |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | thunderbird | 1:68.4.1+build1-0ubuntu0.18.04.1 | USN-4241-1 |
| Ubuntu 16.04 LTS | firefox | 72.0.1+build1-0ubuntu0.16.04.1 | USN-4234-1 |
| Ubuntu 16.04 LTS | thunderbird | 1:68.7.0+build1-0ubuntu0.16.04.2 | USN-4335-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | firefox | 68.4.1-1.el8_1 | RHSA-2020:0111 |
| RHEL 8 | thunderbird | 68.4.1-2.el8_1 | RHSA-2020:0127 |
| RHEL 7 | firefox | 68.4.1-1.el7_7 | RHSA-2020:0085 |
| RHEL 7 | thunderbird | 68.4.1-2.el7_7 | RHSA-2020:0120 |
| RHEL 6 | firefox | 68.4.1-1.el6_10 | RHSA-2020:0086 |
| RHEL 6 | thunderbird | 68.4.1-2.el6_10 | RHSA-2020:0123 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.0 E4S | firefox | 68.4.1-1.el8_0 | RHSA-2020:0295 |
| RHEL 8.0 E4S | thunderbird | 68.4.1-2.el8_0 | RHSA-2020:0292 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | MozillaFirefox +1 | 68.4.1-3.66.1 | SUSE-SU-2020:0142-1, SUSE-SU-2020:0078-1 |
| SLES 15 | MozillaFirefox +1 | 68.4.1-3.66.1 | SUSE-SU-2020:0142-1, SUSE-SU-2020:0078-1 |
| SLES 12 SP5 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES 12 SP4 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES 12 SP3 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES 12 SP1 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES 11 SP4 | MozillaFirefox | 68.4.1-78.57.1 | SUSE-SU-2020:14268-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SLES for SAP 12 SP1 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
| SUSE Enterprise Storage 5 | MozillaFirefox | 68.4.1-109.101.1 | SUSE-SU-2020:0068-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 92.0-1.2 | openSUSE-SU-2024:10600-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 91.1.1-1.1 | openSUSE-SU-2024:10601-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
| openSUSE Leap 15.1 | MozillaFirefox | 68.4.1-lp151.2.24.1 | openSUSE-SU-2020:0060-1 |
| openSUSE Leap 15.1 | MozillaThunderbird | 68.4.1-lp151.2.22.2 | openSUSE-SU-2020:0094-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | librewolf | 71.0.1-r0 | — |
| Alpine v3.23 | firefox +1 | 71.0.1-r0 | — |
| Alpine v3.23 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.22 | firefox +1 | 71.0.1-r0 | — |
| Alpine v3.22 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.21 | firefox +1 | 71.0.1-r0 | — |
| Alpine v3.21 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.20 | firefox | 71.0.1-r0 | — |
| Alpine v3.20 | firefox-esr | 68.4.1-r0 | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | firefox | 71.0.1-r0 | — |
| Alpine v3.19 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.18 | firefox | 71.0.1-r0 | — |
| Alpine v3.18 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.17 | firefox | 71.0.1-r0 | — |
| Alpine v3.17 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.16 | firefox | 71.0.1-r0 | — |
| Alpine v3.16 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.15 | firefox | 71.0.1-r0 | — |
| Alpine v3.15 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.14 | firefox | 71.0.1-r0 | — |
| Alpine v3.14 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.13 | firefox | 71.0.1-r0 | — |
| Alpine v3.13 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.12 | firefox | 71.0.1-r0 | — |
| Alpine v3.12 | firefox-esr | 68.4.1-r0 | — |
| Alpine v3.11 | firefox-esr | 68.4.1-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 68.4.1-2.amzn2.0.1 | ALAS2-2020-1393 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | firefox | 68.4.1-1.0.1.el8_1 | ELSA-2020-0111 |
| Oracle Linux 8 | thunderbird | 68.4.1-2.0.1.el8_1 | ELSA-2020-0127 |
| Oracle Linux 7 | firefox | 68.4.1-1.0.1.el7_7 | ELSA-2020-0085 |
| Oracle Linux 7 | thunderbird | 68.4.1-2.0.1.el7_7 | ELSA-2020-0120 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- Firefox 72 IonMonkey - JIT Type Confusion EDB-49864 · local · May 13, 2021
GitHub 2 repositories
-
maxpl0it/CVE-2019-17026-Exploit ★ 47 · Aug 27, 2020
An exploit for CVE-2019-17026. It pops xcalc and was tested on Ubuntu (x64).
-
lsw29475/CVE-2019-17026 ★ 3 · Feb 24, 2021
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 29
- RHSA-2020:0123 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:0120 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:0085 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:0086 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-4335-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-4241-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-4234-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4603-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-4600-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2093-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2071-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2020:0094-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0078-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0060-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10600-1 MozillaFirefox-92.0-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0068-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:14572-1 firefox-esr-128.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0142-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14268-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2020:0295 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:0292 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:0127 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:0111 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- openSUSE-SU-2024:10601-1 MozillaThunderbird-91.1.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- ALAS2-2020-1393 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Feb 13, 2020
- ELSA-2020-0127 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 18, 2020
- ELSA-2020-0120 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 16, 2020
- ELSA-2020-0111 Critical: firefox security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 15, 2020
- ELSA-2020-0085 Critical: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 13, 2020
References
- https://www.mozilla.org/security/advisories/mfsa2020-04/
- https://www.mozilla.org/security/advisories/mfsa2020-03/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1607443
- GLSA-202003-02 vendor-advisory
- USN-4335-1 vendor-advisory
- http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.html