Description
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM 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=2016375
- 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/