Description
Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a potentially exploitable crash. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | < 85 | — |
| Mozilla | Thunderbird | < 78.7 | — |
| Mozilla | Firefox ESR | < 78.7 | — |
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 | 78.7.0esr-1 | — |
| Debian 14 | thunderbird | 1:78.7.0-1 | — |
| Debian 13 | firefox-esr | 78.7.0esr-1 | — |
| Debian 13 | thunderbird | 1:78.7.0-1 | — |
| Debian 12 | firefox-esr | 78.7.0esr-1 | — |
| Debian 12 | thunderbird | 1:78.7.0-1 | — |
| Debian 10 | firefox-esr | 78.7.0esr-1~deb10u1 | DSA-4840-1 |
| Debian 10 | thunderbird | 1:78.7.0-1~deb10u1 | DSA-4842-1 |
| Debian 9 | firefox-esr | 78.7.0esr-1~deb9u1 | DLA-2539-1 |
| Debian 9 | thunderbird | 1:78.7.0-1~deb9u1 | DLA-2541-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | mozjs78 | No fix yet | — |
| Ubuntu 20.04 LTS | firefox | 85.0+build1-0ubuntu0.20.04.1 | USN-4717-1 |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 20.04 LTS | thunderbird | 1:78.7.1+build1-0ubuntu0.20.04.1 | — |
| Ubuntu 18.04 LTS | firefox | 85.0+build1-0ubuntu0.18.04.1 | USN-4717-1 |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | thunderbird | 1:78.8.1+build1-0ubuntu0.18.04.1 | — |
| Ubuntu 16.04 LTS | firefox | 85.0+build1-0ubuntu0.16.04.1 | USN-4717-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | firefox | 78.7.0-2.el8_3 | RHSA-2021:0288 |
| RHEL 8 | thunderbird | 78.7.0-1.el8_3 | RHSA-2021:0298 |
| RHEL 7 | firefox | 78.7.0-2.el7_9 | RHSA-2021:0290 |
| RHEL 7 | thunderbird | 78.7.0-1.el7_9 | RHSA-2021:0297 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.2 EUS | firefox | 78.7.0-2.el8_2 | RHSA-2021:0289 |
| RHEL 8.2 EUS | thunderbird | 78.7.0-1.el8_2 | RHSA-2021:0299 |
| RHEL 8.1 EUS | firefox | 78.7.0-2.el8_1 | RHSA-2021:0285 |
| RHEL 8.1 EUS | thunderbird | 78.7.0-1.el8_1 | RHSA-2021:0397 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | MozillaFirefox | 78.7.0-8.26.2 | SUSE-SU-2021:0259-1 |
| SLES 15 SP2 | MozillaThunderbird | 78.7.0-8.9.1 | SUSE-SU-2021:0257-1 |
| SLES 15 SP1 | MozillaFirefox | 78.7.0-3.128.2 | SUSE-SU-2021:0246-1 |
| SLES 15 SP1 | MozillaThunderbird | 78.7.0-3.119.1 | SUSE-SU-2021:0245-1 |
| SLES 12 SP5 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SLES 12 SP4 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SLES 12 SP3 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
Show 19 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SLES 11 SP4 | MozillaFirefox | 78.7.0-78.114.1 | SUSE-SU-2021:14609-1 |
| SLES for SAP 15 SP1 | MozillaFirefox | 78.7.0-3.128.2 | SUSE-SU-2021:0246-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SLE HPC 15 SP1 | MozillaFirefox | 78.7.0-3.128.2 | SUSE-SU-2021:0246-1 |
| SUSE OpenStack Cloud Crowbar 9 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SUSE OpenStack Cloud 9 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SUSE Manager Server 4.0 | MozillaFirefox | 78.7.0-3.128.2 | SUSE-SU-2021:0246-1 |
| SUSE Manager Retail Branch Server 4.0 | MozillaFirefox | 78.7.0-3.128.2 | SUSE-SU-2021:0246-1 |
| SUSE Manager Proxy 4.0 | MozillaFirefox | 78.7.0-3.128.2 | SUSE-SU-2021:0246-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
| SUSE Enterprise Storage 6 | MozillaFirefox | 78.7.0-3.128.2 | SUSE-SU-2021:0246-1 |
| SUSE Enterprise Storage 5 | MozillaFirefox | 78.7.0-112.45.1 | SUSE-SU-2021:0241-1 |
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 15.2 | MozillaFirefox | 78.7.0-lp152.2.43.1 | openSUSE-SU-2021:0223-1 |
| openSUSE Leap 15.2 | MozillaThunderbird | 78.7.0-lp152.2.29.1 | openSUSE-SU-2021:0209-1 |
| openSUSE Leap 15.1 | MozillaFirefox | 78.7.0-lp151.2.88.2 | openSUSE-SU-2021:0222-1 |
| openSUSE Leap 15.1 | MozillaThunderbird | 78.7.0-lp151.2.69.1 | openSUSE-SU-2021:0208-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | librewolf | 85.0-r0 | — |
| Alpine v3.23 | firefox +1 | 85.0-r0 | — |
| Alpine v3.23 | firefox-esr +1 | 78.7.0-r0 | — |
| Alpine v3.22 | firefox +1 | 85.0-r0 | — |
| Alpine v3.22 | firefox-esr +1 | 78.7.0-r0 | — |
| Alpine v3.21 | firefox +1 | 85.0-r0 | — |
| Alpine v3.21 | firefox-esr +1 | 78.7.0-r0 | — |
| Alpine v3.20 | firefox | 85.0-r0 | — |
| Alpine v3.20 | firefox-esr +1 | 78.7.0-r0 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | firefox | 85.0-r0 | — |
| Alpine v3.19 | firefox-esr +1 | 78.7.0-r0 | — |
| Alpine v3.18 | firefox | 85.0-r0 | — |
| Alpine v3.18 | firefox-esr +1 | 78.7.0-r0 | — |
| Alpine v3.17 | firefox | 85.0-r0 | — |
| Alpine v3.17 | firefox-esr +1 | 78.7.0-r0 | — |
| Alpine v3.16 | firefox | 85.0-r0 | — |
| Alpine v3.16 | mozjs78 +2 | 78.7.0-r0 | — |
| Alpine v3.15 | firefox | 85.0-r0 | — |
| Alpine v3.15 | mozjs78 +1 | 78.7.0-r0 | — |
| Alpine v3.14 | firefox | 85.0-r0 | — |
| Alpine v3.14 | mozjs78 +1 | 78.7.0-r0 | — |
| Alpine v3.13 | firefox | 85.0-r0 | — |
| Alpine v3.13 | mozjs78 +1 | 78.7.0-r0 | — |
| Alpine v3.12 | firefox-esr | 78.7.0-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 78.7.0-1.amzn2 | ALAS2-2021-1603 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | firefox | 78.7.0-2.0.1.el8_3 | ELSA-2021-0288 |
| Oracle Linux 8 | thunderbird | 78.7.0-1.0.1.el8_3 | ELSA-2021-0298 |
| Oracle Linux 7 | firefox | 78.7.0-2.0.1.el7_9 | ELSA-2021-0290 |
| Oracle Linux 7 | thunderbird | 78.7.0-1.0.1.el7_9 | ELSA-2021-0297 |
Advisories 31
- RHSA-2021:0290 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2021:0297 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-4717-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4842-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-4840-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2541-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2539-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2021:0241-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0257-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0246-1 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
- SUSE-SU-2021:0259-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0222-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:14609-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0208-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0245-1 Security update for MozillaThunderbird 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-2021:0223-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2021:0397 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:0299 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:0298 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:0289 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:0288 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:0285 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- openSUSE-SU-2021:0209-1 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
- ALAS2-2021-1603 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Feb 19, 2021
- ELSA-2021-0298 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 29, 2021
- ELSA-2021-0297 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 29, 2021
- ELSA-2021-0288 Important: firefox security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 28, 2021
- ELSA-2021-0290 Important: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 28, 2021