Description
Memory safety bugs present in Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 149.0.2, Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | — | 115.34.1 |
| Mozilla | Thunderbird | — | 140.9.1 |
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 | 140.9.1esr-1 | — |
| Debian 14 | thunderbird | 1:140.9.1esr-1 | — |
| Debian 13 | firefox-esr | 140.9.1esr-1~deb13u1 | — |
| Debian 13 | thunderbird | 1:140.9.1esr-1~deb13u1 | — |
| Debian 12 | firefox-esr | 140.9.1esr-1~deb12u1 | — |
| Debian 12 | thunderbird | 1:140.9.1esr-1~deb12u1 | — |
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 | 140.9.1-1.el10_1 | RHSA-2026:9638, RHSA-2026:7672 |
| RHEL 9 | firefox +2 | 140.9.1-1.el9_7 | RHSA-2026:8459, RHSA-2026:7671 |
| RHEL 8 | firefox +1 | 140.9.1-1.el8_10 | RHSA-2026:9345, RHSA-2026:8052 |
Show 14 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | firefox +1 | 140.9.1-1.el10_0 | RHSA-2026:13665, RHSA-2026:11813 |
| RHEL 9.6 EUS | firefox +2 | 140.9.1-1.el9_6 | RHSA-2026:13583, RHSA-2026:13342 |
| RHEL 9.4 EUS | firefox +2 | 140.9.1-1.el9_4 | RHSA-2026:13582, RHSA-2026:13533 |
| RHEL 9.2 E4S | firefox +2 | 140.9.1-1.el9_2 | RHSA-2026:13922, RHSA-2026:13412 |
| RHEL 9.0 E4S | firefox +1 | 140.9.1-1.el9_0 | RHSA-2026:13596, RHSA-2026:12264 |
| RHEL 8.8 TUS | firefox +1 | 140.9.1-1.el8_8 | RHSA-2026:14223, RHSA-2026:13682 |
| RHEL 8.8 E4S | firefox +1 | 140.9.1-1.el8_8 | RHSA-2026:14223, RHSA-2026:13682 |
| RHEL 8.6 TUS | firefox +1 | 140.9.1-1.el8_6 | RHSA-2026:15889, RHSA-2026:13683 |
| RHEL 8.6 E4S | firefox +1 | 140.9.1-1.el8_6 | RHSA-2026:15889, RHSA-2026:13683 |
| RHEL 8.6 AUS | firefox +1 | 140.9.1-1.el8_6 | RHSA-2026:15889, RHSA-2026:13683 |
| RHEL 8.4 EUS Long Life | firefox +1 | 140.9.1-1.el8_4 | RHSA-2026:14303, RHSA-2026:13600 |
| RHEL 8.4 AUS | firefox +1 | 140.9.1-1.el8_4 | RHSA-2026:14303, RHSA-2026:13600 |
| RHEL 8.2 AUS | firefox | 140.9.1-1.el8_2 | RHSA-2026:11805 |
| RHEL 7 ELS | firefox | 140.9.1-2.el7_9 | RHSA-2026:13977 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | firefox | 140.9.1-1.el10_1 | ALSA-2026:7672 |
| AlmaLinux 10 | thunderbird | 140.9.1-1.el10_1.alma.1 | ALSA-2026:9638 |
| AlmaLinux 9 | firefox +2 | 140.9.1-1.el9_7.alma.1 | ALSA-2026:8459, ALSA-2026:7671 |
| AlmaLinux 8 | firefox +1 | 140.9.1-1.el8_10.alma.1 | ALSA-2026:9345, ALSA-2026:8052 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | firefox +1 | 140.9.1-1.el10_1 | RLSA-2026:9638, RLSA-2026:7672 |
| Rocky Linux 9 | firefox +1 | 140.9.1-1.el9_7 | RLSA-2026:8459, RLSA-2026:7671 |
| Rocky Linux 8 | firefox +1 | 140.9.1-1.el8_10 | RLSA-2026:9345, RLSA-2026:8052 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLES 15 SP7 | MozillaThunderbird | 140.9.1-150200.8.266.1 | SUSE-SU-2026:1379-1 |
| SLES 15 SP6 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLES 15 SP5 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLES 15 SP4 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLES 12 SP5 | MozillaFirefox | 140.9.1-112.307.1 | SUSE-SU-2026:1273-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | MozillaFirefox | 140.9.1-160000.1.1 | SUSE-SU-2026:21157-1 |
| SLES for SAP 15 SP6 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLES for SAP 15 SP5 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLES for SAP 15 SP4 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLES 16.0 | MozillaFirefox | 140.9.1-160000.1.1 | SUSE-SU-2026:21157-1 |
| SLE HPC 15 SP5 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
| SLE HPC 15 SP4 | MozillaFirefox | 140.9.1-150200.152.228.1 | SUSE-SU-2026:1322-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 149.0.2-1.1 | openSUSE-SU-2026:10511-1 |
| openSUSE Tumbleweed | firefox-esr +1 | 140.9.1-1.1 | openSUSE-SU-2026:10503-1, openSUSE-SU-2026:10501-1 |
| openSUSE Leap 16.0 | MozillaFirefox | 140.9.1-160000.1.1 | openSUSE-SU-2026:20486-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | firefox | 140.9.1-1.amzn2023.0.1 | ALAS2023-2026-1621 |
| Amazon Linux 2 | thunderbird | 140.9.1-1.amzn2.0.1 | ALAS2-2026-3271 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | firefox +1 | 140.9.1-1.0.1.el10_1 | ELSA-2026-9638, ELSA-2026-7672 |
| Oracle Linux 9 | firefox +2 | 140.9.1-1.0.1.el9_7 | ELSA-2026-8459, ELSA-2026-7671 |
| Oracle Linux 8 | firefox +1 | 140.9.1-1.0.1.el8_10 | ELSA-2026-9345, ELSA-2026-8052 |
| Oracle Linux 7 | firefox | 140.9.1-1.0.1.el7_9 | ELSA-2026-13977 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | firefox | 151.0.2-r0 | — |
Advisories 50
- WID-SEC-2026-2455 Oracle Solaris Drittanbieterkomponenten: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- WID-SEC-2026-0997 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
- ALSA-2026:7672 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:9638 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:8459 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:7671 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:9345 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:8052 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2026:9638 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:9345 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:8459 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:8052 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:7672 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:7671 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:15889 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:14223 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:14303 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13977 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13922 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13683 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13682 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13665 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13596 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13600 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13582 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13583 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13533 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13412 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:13342 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:12264 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:11813 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:11805 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- WID-SEC-2026-1730 Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff BSI CERT-Bund (WID) · Jul 16, 2026
- ELSA-2026-13977 Important: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jun 11, 2026
- ALAS2023-2026-1621 Important: firefox security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 30, 2026
- ALAS2-2026-3271 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Apr 29, 2026
- RLSA-2026:9638 Important: thunderbird security update Rocky Linux Security Advisories · Apr 24, 2026
- RLSA-2026:9345 Important: thunderbird security update Rocky Linux Security Advisories · Apr 23, 2026
- openSUSE-SU-2026:20486-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:21157-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Apr 22, 2026
- ELSA-2026-9638 Important: thunderbird security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Apr 22, 2026
- ELSA-2026-9345 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 21, 2026
- RLSA-2026:8459 Important: thunderbird security update Rocky Linux Security Advisories · Apr 19, 2026
- SUSE-SU-2026:1379-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Apr 17, 2026
- RLSA-2026:8052 Important: firefox security update Rocky Linux Security Advisories · Apr 16, 2026
- ELSA-2026-8459 Important: thunderbird security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Apr 16, 2026
- RLSA-2026:7671 Important: firefox security update Rocky Linux Security Advisories · Apr 15, 2026
- RLSA-2026:7672 Important: firefox security update Rocky Linux Security Advisories · Apr 15, 2026
- SUSE-SU-2026:1322-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Apr 15, 2026
- SUSE-SU-2026:1273-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Apr 14, 2026
References
- Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2
- https://www.mozilla.org/security/advisories/mfsa2026-25/
- https://www.mozilla.org/security/advisories/mfsa2026-26/
- https://www.mozilla.org/security/advisories/mfsa2026-27/
- https://www.mozilla.org/security/advisories/mfsa2026-28/
- https://www.mozilla.org/security/advisories/mfsa2026-29/