Description
Memory safety bugs present in Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141 and Thunderbird 141. 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 142, Firefox ESR 140.2, Thunderbird 142, and Thunderbird 140.2.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | — | 140.2 |
| Mozilla | Thunderbird | — | 140.2 |
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.
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 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLES 15 SP7 | MozillaThunderbird | 140.2.0-150200.8.236.1 | SUSE-SU-2025:03007-1 |
| SLES 15 SP6 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLES 15 SP6 | MozillaThunderbird | 140.2.0-150200.8.236.1 | SUSE-SU-2025:03007-1 |
| SLES 15 SP5 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLES 15 SP4 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLES 15 SP3 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | MozillaFirefox | 140.2.0-112.276.1 | SUSE-SU-2025:03009-1 |
| SLES for SAP 15 SP5 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLES for SAP 15 SP4 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLES for SAP 15 SP3 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLE HPC 15 SP5 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLE HPC 15 SP4 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SLE HPC 15 SP3 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| SUSE Enterprise Storage 7.1 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 142.0.1-1.1 | openSUSE-SU-2025:15516-1 |
| openSUSE Tumbleweed | firefox-esr +1 | 140.2.0-1.1 | openSUSE-SU-2025:15472-1, openSUSE-SU-2025:15467-1 |
| openSUSE Leap 15.6 | MozillaFirefox | 140.2.0-150200.152.198.1 | SUSE-SU-2025:03008-1 |
| openSUSE Leap 15.6 | MozillaThunderbird | 140.2.0-150200.8.236.1 | SUSE-SU-2025:03007-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | firefox | 140.2.0-1.amzn2023.0.1 | ALAS2023-2025-1171 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | firefox | 140.2-r0 | — |
Advisories 8
- WID-SEC-2025-1866 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 15, 2026
- openSUSE-SU-2025:15516-1 MozillaFirefox-142.0.1-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2025:15467-1 firefox-esr-140.2.0-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2025:15472-1 MozillaThunderbird-140.2.0-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:03009-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:03008-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:03007-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2023-2025-1171 Important: firefox security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 8, 2025
References
- Memory safety bugs fixed in Firefox ESR 140.2, Thunderbird ESR 140.2, Firefox 142 and Thunderbird 142
- https://www.mozilla.org/security/advisories/mfsa2025-64/
- https://www.mozilla.org/security/advisories/mfsa2025-67/
- https://www.mozilla.org/security/advisories/mfsa2025-70/
- https://www.mozilla.org/security/advisories/mfsa2025-72/