Description
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | — | 115.34 |
| Mozilla | Thunderbird | — | 140.9 |
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 | 140.9.0esr-1 | — |
| Debian 14 | thunderbird | 1:140.9.0esr-1 | — |
| Debian 13 | firefox-esr | 140.9.0esr-1~deb13u1 | DSA-6178-1 |
| Debian 13 | thunderbird | 1:140.9.0esr-1~deb13u1 | DSA-6179-1 |
| Debian 12 | firefox-esr | 140.9.0esr-1~deb12u1 | DSA-6178-1 |
| Debian 12 | thunderbird | 1:140.9.0esr-1~deb12u1 | DSA-6179-1 |
| Debian 11 | firefox-esr | 140.9.0esr-1~deb11u1 | DLA-4510-1 |
| Debian 11 | thunderbird | 1:140.9.0esr-1~deb11u1 | DLA-4511-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | mozjs102 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | mozjs78 +3 | No fix yet | — |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | firefox +1 | 140.9.0-1.el10_1 | RHSA-2026:6342, RHSA-2026:5931 |
| RHEL 9 | firefox +2 | 140.9.0-1.el9_7 | RHSA-2026:6188, RHSA-2026:5930 |
| RHEL 8 | firefox +1 | 140.9.0-1.el8_10 | RHSA-2026:6917, RHSA-2026:5932 |
Show 14 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | firefox +1 | 140.9.0-1.el10_0 | RHSA-2026:8315, RHSA-2026:7843 |
| RHEL 9.6 EUS | firefox +2 | 140.9.0-1.el9_6 | RHSA-2026:8284, RHSA-2026:7837 |
| RHEL 9.4 EUS | firefox +2 | 140.9.0-1.el9_4 | RHSA-2026:8290, RHSA-2026:7845 |
| RHEL 9.2 E4S | firefox +2 | 140.9.0-1.el9_2 | RHSA-2026:8287, RHSA-2026:7841 |
| RHEL 9.0 E4S | firefox +1 | 140.9.0-1.el9_0 | RHSA-2026:8286, RHSA-2026:7839 |
| RHEL 8.8 TUS | firefox +1 | 140.9.0-1.el8_8 | RHSA-2026:8288, RHSA-2026:7838 |
| RHEL 8.8 E4S | firefox +1 | 140.9.0-1.el8_8 | RHSA-2026:8288, RHSA-2026:7838 |
| RHEL 8.6 TUS | firefox +1 | 140.9.0-1.el8_6 | RHSA-2026:8289, RHSA-2026:7842 |
| RHEL 8.6 E4S | firefox +1 | 140.9.0-1.el8_6 | RHSA-2026:8289, RHSA-2026:7842 |
| RHEL 8.6 AUS | firefox +1 | 140.9.0-1.el8_6 | RHSA-2026:8289, RHSA-2026:7842 |
| RHEL 8.4 EUS Long Life | firefox +1 | 140.9.0-1.el8_4 | RHSA-2026:8850, RHSA-2026:7858 |
| RHEL 8.4 AUS | firefox +1 | 140.9.0-1.el8_4 | RHSA-2026:8850, RHSA-2026:7858 |
| RHEL 8.2 AUS | firefox +1 | 140.9.0-1.el8_2 | RHSA-2026:8285, RHSA-2026:7840 |
| RHEL 7 ELS | firefox | 140.9.0-1.el7_9 | RHSA-2026:8427 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | firefox | 140.9.0-1.el10_1 | ALSA-2026:5931 |
| AlmaLinux 10 | thunderbird | 140.9.0-1.el10_1.alma.1 | ALSA-2026:6342 |
| AlmaLinux 9 | firefox +2 | 140.9.0-1.el9_7.alma.1 | ALSA-2026:6188, ALSA-2026:5930 |
| AlmaLinux 8 | firefox +1 | 140.9.0-1.el8_10.alma.1 | ALSA-2026:6917, ALSA-2026:5932 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | firefox +1 | 140.9.0-1.el10_1 | RLSA-2026:6342, RLSA-2026:5931 |
| Rocky Linux 9 | firefox +1 | 140.9.0-1.el9_7 | RLSA-2026:6188, RLSA-2026:5930 |
| Rocky Linux 8 | firefox +1 | 140.9.0-1.el8_10 | RLSA-2026:6917, RLSA-2026:5932 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLES 15 SP6 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLES 15 SP5 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLES 15 SP4 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLES 12 SP5 | MozillaFirefox | 140.9.0-112.304.2 | SUSE-SU-2026:1127-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | MozillaFirefox | 140.9.0-160000.1.1 | SUSE-SU-2026:20978-1 |
| SLES for SAP 15 SP6 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLES for SAP 15 SP5 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLES for SAP 15 SP4 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLES 16.0 | MozillaFirefox | 140.9.0-160000.1.1 | SUSE-SU-2026:20978-1 |
| SLE HPC 15 SP5 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| SLE HPC 15 SP4 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 149.0-1.1 | openSUSE-SU-2026:10458-1 |
| openSUSE Tumbleweed | firefox-esr +1 | 140.9.0-1.1 | openSUSE-SU-2026:10447-1, openSUSE-SU-2026:10413-1 |
| openSUSE Leap 16.0 | MozillaFirefox | 140.9.0-160000.1.1 | openSUSE-SU-2026:20439-1 |
| openSUSE Leap 15.6 | MozillaFirefox | 140.9.0-150200.152.225.1 | SUSE-SU-2026:1126-1 |
| openSUSE Leap 15.6 | MozillaThunderbird | 140.9.0-150200.8.263.1 | SUSE-SU-2026:1163-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | firefox | 140.9.0-1.amzn2023.0.2 | ALAS2023-2026-1554 |
| Amazon Linux 2 | thunderbird | 140.9.0-1.amzn2.0.2 | ALAS2-2026-3241 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | firefox +1 | 140.9.0-1.0.1.el10_1 | ELSA-2026-6342, ELSA-2026-5931 |
| Oracle Linux 9 | firefox +2 | 140.9.0-1.0.1.el9_7 | ELSA-2026-6188, ELSA-2026-5930 |
| Oracle Linux 8 | firefox +1 | 140.9.0-1.0.1.el8_10 | ELSA-2026-6917, ELSA-2026-5932 |
| Oracle Linux 7 | firefox | 140.9.0-1.0.1.el7_9 | ELSA-2026-8427 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | firefox | 149.0-r0 | — |
Advisories 50
- WID-SEC-2026-0850 Mozilla Firefox und Mozilla Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
- ALSA-2026:5931 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:6342 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:6188 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:5930 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:6917 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:5932 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2026-1730 Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff BSI CERT-Bund (WID) · Jul 16, 2026
- RHSA-2026:8850 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8427 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8315 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8290 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8288 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8289 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8286 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8287 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8284 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:8285 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7858 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7843 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7845 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7842 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7840 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7841 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7838 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7839 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:7837 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:6917 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:6342 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:6188 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:5931 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:5932 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- RHSA-2026:5930 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jul 15, 2026
- ELSA-2026-8427 Important: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jun 11, 2026
- ALAS2-2026-3241 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Apr 13, 2026
- ALAS2023-2026-1554 Important: firefox security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 13, 2026
- RLSA-2026:6917 Important: thunderbird security update Rocky Linux Security Advisories · Apr 12, 2026
- SUSE-SU-2026:20978-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Apr 10, 2026
- RLSA-2026:6342 Important: thunderbird security update Rocky Linux Security Advisories · Apr 9, 2026
- RLSA-2026:5931 Important: firefox security update Rocky Linux Security Advisories · Apr 9, 2026
- RLSA-2026:6188 Important: thunderbird security update Rocky Linux Security Advisories · Apr 7, 2026
- RLSA-2026:5930 Important: firefox security update Rocky Linux Security Advisories · Apr 7, 2026
- RLSA-2026:5932 Important: firefox security update Rocky Linux Security Advisories · Apr 7, 2026
- ELSA-2026-6917 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 7, 2026
- openSUSE-SU-2026:20439-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Apr 3, 2026
- SUSE-SU-2026:1163-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Apr 2, 2026
- ELSA-2026-6342 Important: thunderbird security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Apr 1, 2026
- openSUSE-SU-2026:10458-1 MozillaFirefox-149.0-1.1 on GA media SUSE / openSUSE Security Updates · Mar 30, 2026
- ELSA-2026-6188 Important: thunderbird security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Mar 30, 2026
- SUSE-SU-2026:1126-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Mar 29, 2026
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2020906
- https://www.mozilla.org/security/advisories/mfsa2026-20/
- https://www.mozilla.org/security/advisories/mfsa2026-21/
- https://www.mozilla.org/security/advisories/mfsa2026-22/
- https://www.mozilla.org/security/advisories/mfsa2026-23/
- https://www.mozilla.org/security/advisories/mfsa2026-24/