Description
Memory safety bugs present in Firefox ESR 140.2, Thunderbird ESR 140.2, Firefox 142 and Thunderbird 142. 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 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird 140.3.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | — | 140.3 |
| Mozilla | Thunderbird | — | 140.3 |
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 | 140.3.0esr-1 | — |
| Debian 14 | thunderbird | 1:140.3.0esr-1 | — |
| Debian 13 | firefox-esr | 140.3.0esr-1~deb13u1 | DSA-6003-1 |
| Debian 13 | thunderbird | 1:140.3.0esr-1~deb13u1 | DSA-6011-1 |
| Debian 12 | firefox-esr | 140.3.0esr-1~deb12u1 | DSA-6003-1 |
| Debian 12 | thunderbird | 1:140.3.0esr-1~deb12u1 | DSA-6011-1 |
| Debian 11 | firefox-esr | 140.3.0esr-1~deb11u2 | DLA-4305-1 |
| Debian 11 | thunderbird | 1:140.3.0esr-1~deb11u1 | DLA-4311-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | mozjs102 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | mozjs78 +2 | No fix yet | — |
| Ubuntu 22.04 LTS | thunderbird | 1:140.7.1+build1-0ubuntu0.22.04.1 | — |
| 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 | 140.3.0-1.el10_0 | RHSA-2025:16157, RHSA-2025:16109 |
| RHEL 9 | firefox +2 | 140.3.0-1.el9_6 | RHSA-2025:16156, RHSA-2025:16108 |
| RHEL 8 | firefox +1 | 140.3.0-1.el8_10 | RHSA-2025:16589, RHSA-2025:16260 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.4 EUS | firefox +2 | 140.3.0-1.el9_4 | RHSA-2025:17378, RHSA-2025:17346 |
| RHEL 9.2 E4S | firefox +2 | 140.3.0-1.el9_2 | RHSA-2025:17374, RHSA-2025:17345 |
| RHEL 9.0 E4S | firefox +1 | 140.3.0-1.el9_0 | RHSA-2025:17373, RHSA-2025:17344 |
| RHEL 8.8 TUS | firefox +1 | 140.3.0-1.el8_8 | RHSA-2025:17368, RHSA-2025:17343 |
| RHEL 8.8 E4S | firefox +1 | 140.3.0-1.el8_8 | RHSA-2025:17368, RHSA-2025:17343 |
| RHEL 8.6 TUS | firefox +1 | 140.3.0-1.el8_6 | RHSA-2025:17367, RHSA-2025:17342 |
| RHEL 8.6 E4S | firefox +1 | 140.3.0-1.el8_6 | RHSA-2025:17367, RHSA-2025:17342 |
| RHEL 8.6 AUS | firefox +1 | 140.3.0-1.el8_6 | RHSA-2025:17367, RHSA-2025:17342 |
| RHEL 8.4 EUS Long Life | firefox +1 | 140.3.0-1.el8_4 | RHSA-2025:17371, RHSA-2025:17341 |
| RHEL 8.4 AUS | firefox +1 | 140.3.0-1.el8_4 | RHSA-2025:17371, RHSA-2025:17341 |
| RHEL 8.2 AUS | firefox +1 | 140.3.0-1.el8_2 | RHSA-2025:17372, RHSA-2025:17340 |
| RHEL 7 ELS | firefox | 140.3.0-1.el7_9 | RHSA-2025:17453 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | firefox | 140.3.0-1.el10_0 | ALSA-2025:16109 |
| AlmaLinux 10 | thunderbird | 140.3.0-1.el10_0.alma.1 | ALSA-2025:16157 |
| AlmaLinux 9 | firefox +2 | 140.3.0-1.el9_6.alma.1 | ALSA-2025:16156, ALSA-2025:16108 |
| AlmaLinux 8 | firefox +1 | 140.3.0-1.el8_10.alma.1 | ALSA-2025:16589, ALSA-2025:16260 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | firefox +1 | 140.3.0-1.el10_0 | RLSA-2025:16157, RLSA-2025:16109 |
| Rocky Linux 9 | firefox +1 | 140.3.0-1.el9_6 | RLSA-2025:16156, RLSA-2025:16108 |
| Rocky Linux 8 | firefox +1 | 140.3.0-1.el8_10 | RLSA-2025:16589, RLSA-2025:16260 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLES 15 SP7 | MozillaThunderbird | 140.3.0-150200.8.239.1 | SUSE-SU-2025:03309-1 |
| SLES 15 SP6 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLES 15 SP6 | MozillaThunderbird | 140.3.0-150200.8.239.1 | SUSE-SU-2025:03309-1 |
| SLES 15 SP5 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLES 15 SP4 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLES 15 SP3 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | MozillaFirefox | 140.3.0-112.279.1 | SUSE-SU-2025:03287-1 |
| SLES for SAP 16.0 | MozillaFirefox | 140.5.0-160000.1.1 | SUSE-SU-2025:21021-1 |
| SLES for SAP 15 SP5 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLES for SAP 15 SP4 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLES for SAP 15 SP3 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLES 16.0 | MozillaFirefox | 140.5.0-160000.1.1 | SUSE-SU-2025:21021-1 |
| SLE HPC 15 SP5 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLE HPC 15 SP4 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SLE HPC 15 SP3 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| SUSE Enterprise Storage 7.1 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 143.0-1.1 | openSUSE-SU-2025:15565-1 |
| openSUSE Tumbleweed | firefox-esr +1 | 140.3.0-1.1 | openSUSE-SU-2025:15560-1, openSUSE-SU-2025:15555-1 |
| openSUSE Leap 16.0 | MozillaFirefox | 140.5.0-160000.1.1 | openSUSE-SU-2025:20065-1 |
| openSUSE Leap 16.0 | MozillaThunderbird | 140.3.0-bp160.1.1 | openSUSE-SU-2025:20021-1 |
| openSUSE Leap 15.6 | MozillaFirefox | 140.3.0-150200.152.201.1 | SUSE-SU-2025:03291-1 |
| openSUSE Leap 15.6 | MozillaThunderbird | 140.3.0-150200.8.239.1 | SUSE-SU-2025:03309-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | firefox | 140.3.0-1.amzn2023.0.1 | ALAS2023-2025-1203 |
| Amazon Linux 2 | thunderbird | 140.3.0-1.amzn2.0.1 | ALAS2-2025-3008 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | firefox +1 | 140.3.0-1.0.1.el10_0 | ELSA-2025-16157, ELSA-2025-16109 |
| Oracle Linux 9 | firefox +2 | 140.3.0-1.0.1.el9_6 | ELSA-2025-16156, ELSA-2025-16108 |
| Oracle Linux 8 | firefox +1 | 140.3.0-1.0.1.el8_10 | ELSA-2025-16589, ELSA-2025-16260 |
| Oracle Linux 7 | firefox | 140.3.0-1.0.1.el7_9 | ELSA-2025-17453 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | firefox | 140.3-r0 | — |
Advisories 50
- SUSE-SU-2025:03287-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Nov 10, 2026
- ALSA-2025:16109 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:16157 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:16108 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:16156 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:16589 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:16260 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2025:17453 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17378 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17373 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17374 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17371 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17372 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17367 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17368 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17346 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17345 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17343 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17344 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17342 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17340 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:17341 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:16589 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:16260 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:16109 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:16156 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:16157 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:16108 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- WID-SEC-2025-2074 Mozilla Firefox, Firefox ESR und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 15, 2026
- openSUSE-SU-2025:20065-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2025:20021-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2025:15560-1 MozillaThunderbird-140.3.0-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2025:15565-1 MozillaFirefox-143.0-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2025:15555-1 firefox-esr-140.3.0-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:03291-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:03309-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:21021-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Mar 23, 2026
- DSA-6003-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-4305-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- ELSA-2025-17453 Important: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Dec 15, 2025
- RLSA-2025:16156 Important: thunderbird security update Rocky Linux Security Advisories · Oct 10, 2025
- RLSA-2025:16108 Important: firefox security update Rocky Linux Security Advisories · Oct 10, 2025
- RLSA-2025:16260 Important: firefox security update Rocky Linux Security Advisories · Oct 8, 2025
- RLSA-2025:16589 Important: thunderbird security update Rocky Linux Security Advisories · Oct 8, 2025
- RLSA-2025:16109 Important: firefox security update Rocky Linux Security Advisories · Oct 8, 2025
- RLSA-2025:16157 Important: thunderbird security update Rocky Linux Security Advisories · Oct 3, 2025
- ALAS2-2025-3008 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 29, 2025
- ALAS2023-2025-1203 Important: firefox security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 29, 2025
- DLA-4311-1 thunderbird - security update Debian Security (DSA / DLA) · Sep 26, 2025
- DSA-6011-1 thunderbird - security update Debian Security (DSA / DLA) · Sep 25, 2025
References
- Memory safety bugs fixed in Firefox ESR 140.3, Thunderbird ESR 140.3, Firefox 143 and Thunderbird 143
- https://www.mozilla.org/security/advisories/mfsa2025-73/
- https://www.mozilla.org/security/advisories/mfsa2025-75/
- https://www.mozilla.org/security/advisories/mfsa2025-77/
- https://www.mozilla.org/security/advisories/mfsa2025-78/