Description
A locally-installed hostile program could send `WM_COPYDATA` messages that Firefox would process incorrectly, leading to an out-of-bounds read. *This bug only affects Firefox on Windows. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 78.11, Firefox < 89, and Firefox ESR < 78.11.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | unspecified – < 78.11 | 78.11 |
| Mozilla | Firefox | unspecified – < 89 | 89 |
| Mozilla | Firefox ESR | unspecified – < 78.11 | 78.11 |
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 22.04 LTS | mozjs78 | No fix yet | — |
| 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 SP3 | MozillaFirefox | 78.11.0-8.43.1 | SUSE-SU-2021:1884-1 |
| SLES 15 SP3 | MozillaThunderbird | 78.11.0-8.30.1 | SUSE-SU-2021:2003-1 |
| SLES 15 SP2 | MozillaFirefox | 78.11.0-8.43.1 | SUSE-SU-2021:1884-1 |
| SLES 15 SP2 | MozillaThunderbird | 78.11.0-8.30.1 | SUSE-SU-2021:2003-1 |
| SLES 15 SP1 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SLES 15 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SLES 12 SP5 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
Show 20 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SLES 12 SP3 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SLES 12 SP2 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SLES 11 SP4 | MozillaFirefox | 78.11.0-78.131.1 | SUSE-SU-2021:14743-1 |
| SLES for SAP 15 SP1 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SLES for SAP 15 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SLE HPC 15 SP1 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SLE HPC 15 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SUSE OpenStack Cloud Crowbar 9 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SUSE OpenStack Cloud 9 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SUSE Manager Server 4.0 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SUSE Manager Retail Branch Server 4.0 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SUSE Manager Proxy 4.0 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 78.11.0-112.62.1 | SUSE-SU-2021:1886-1 |
| SUSE Enterprise Storage 6 | MozillaFirefox | 78.11.0-3.144.1 | SUSE-SU-2021:1919-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 92.0-1.2 | openSUSE-SU-2024:10600-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 91.1.1-1.1 | openSUSE-SU-2024:10601-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
| openSUSE Leap 15.3 | MozillaFirefox | 78.11.0-8.43.1 | openSUSE-SU-2021:1884-1 |
| openSUSE Leap 15.3 | MozillaThunderbird | 78.11.0-8.30.1 | openSUSE-SU-2021:2003-1 |
| openSUSE Leap 15.2 | MozillaFirefox | 78.11.0-lp152.2.58.1 | openSUSE-SU-2021:0858-1 |
| openSUSE Leap 15.2 | MozillaThunderbird | 78.11.0-lp152.2.45.1 | openSUSE-SU-2021:0910-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.23 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.22 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.21 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.20 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.19 | thunderbird | 91.3.2-r0 | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.18 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.17 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.16 | thunderbird | 91.3.2-r0 | — |
Advisories 12
- openSUSE-SU-2021:0910-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1884-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2003-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1886-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1919-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10600-1 MozillaFirefox-92.0-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1884-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0858-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:14572-1 firefox-esr-128.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:2003-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · May 7, 2025
- openSUSE-SU-2024:10601-1 MozillaThunderbird-91.1.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- SUSE-SU-2021:14743-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · May 2, 2025