Description
Under certain conditions, when handling a ReadableStream, a race condition can cause a use-after-free. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Thunderbird < 68.7.0, Firefox < 74.0.1, and Firefox ESR < 68.6.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | unspecified – < 68.7.0 | 68.7.0 |
| Mozilla | Firefox | unspecified – < 74.0.1 | 74.0.1 |
| Mozilla | Firefox ESR | unspecified – < 68.6.1 | 68.6.1 |
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 | 68.6.1esr-1 | — |
| Debian 14 | thunderbird | 1:68.7.0-1 | — |
| Debian 13 | firefox-esr | 68.6.1esr-1 | — |
| Debian 13 | thunderbird | 1:68.7.0-1 | — |
| Debian 12 | firefox-esr | 68.6.1esr-1 | — |
| Debian 12 | thunderbird | 1:68.7.0-1 | — |
| Debian 10 | firefox-esr | 68.6.1esr-1~deb10u1 | DSA-4653-1 |
| Debian 10 | thunderbird | 1:68.7.0-1~deb10u1 | DSA-4656-1 |
| Debian 9 | firefox-esr | 68.6.1esr-1~deb9u1 | DSA-4653-1 |
| Debian 9 | thunderbird | 1:68.7.0-1~deb9u1 | DSA-4656-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 8 | firefox-esr | 68.7.0esr-1~deb8u1 | DLA-2170-1 |
| Debian 8 | thunderbird | 1:68.7.0-1~deb8u1 | DLA-2172-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | firefox | 75.0+build3-0ubuntu1 | — |
| Ubuntu 20.04 LTS | thunderbird | 1:68.7.0+build1-0ubuntu1 | — |
| Ubuntu 18.04 LTS | firefox | 74.0.1+build1-0ubuntu0.18.04.1 | USN-4317-1 |
| Ubuntu 18.04 LTS | thunderbird | 1:68.7.0+build1-0ubuntu0.18.04.1 | USN-4328-1 |
| Ubuntu 16.04 LTS | firefox | 74.0.1+build1-0ubuntu0.16.04.1 | USN-4317-1 |
| Ubuntu 16.04 LTS | thunderbird | 1:68.7.0+build1-0ubuntu0.16.04.2 | USN-4335-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | firefox | 68.6.1-1.el8_1 | RHSA-2020:1341 |
| RHEL 8 | thunderbird | 68.7.0-1.el8_1 | RHSA-2020:1495 |
| RHEL 7 | firefox | 68.6.1-1.el7_8 | RHSA-2020:1338 |
| RHEL 7 | thunderbird | 68.7.0-1.el7_8 | RHSA-2020:1489 |
| RHEL 6 | firefox | 68.6.1-1.el6_10 | RHSA-2020:1339 |
| RHEL 6 | thunderbird | 68.7.0-1.el6_10 | RHSA-2020:1488 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.0 E4S | firefox | 68.6.1-1.el8_0 | RHSA-2020:1340 |
| RHEL 8.0 E4S | thunderbird | 68.7.0-1.el8_0 | RHSA-2020:1496 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | MozillaFirefox | 68.6.1-3.81.1 | SUSE-SU-2020:0929-1 |
| SLES 15 SP1 | MozillaThunderbird | 68.7.0-3.77.1 | SUSE-SU-2020:1027-1 |
| SLES 12 SP5 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES 12 SP4 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES 12 SP3 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES 12 SP2 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES 11 SP4 | MozillaFirefox | 68.6.1-78.67.1 | SUSE-SU-2020:14337-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SLES for SAP 12 SP1 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
| SUSE Enterprise Storage 5 | MozillaFirefox | 68.6.1-109.113.1 | SUSE-SU-2020:0928-1 |
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 15.1 | MozillaFirefox | 68.6.1-lp151.2.39.1 | openSUSE-SU-2020:0461-1 |
| openSUSE Leap 15.1 | MozillaThunderbird | 68.7.0-lp151.2.31.1 | openSUSE-SU-2020:0544-1, openSUSE-SU-2020:0520-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | librewolf | 74.0.1-r0 | — |
| Alpine v3.23 | firefox +1 | 74.0.1-r0 | — |
| Alpine v3.23 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.23 | thunderbird | 68.7.0-r0 | — |
| Alpine v3.22 | firefox +1 | 74.0.1-r0 | — |
| Alpine v3.22 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.22 | thunderbird | 68.7.0-r0 | — |
| Alpine v3.21 | firefox +1 | 74.0.1-r0 | — |
| Alpine v3.21 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.21 | thunderbird | 68.7.0-r0 | — |
| Alpine v3.20 | firefox | 74.0.1-r0 | — |
| Alpine v3.20 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.20 | thunderbird | 68.7.0-r0 | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | firefox | 74.0.1-r0 | — |
| Alpine v3.19 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.19 | thunderbird | 68.7.0-r0 | — |
| Alpine v3.18 | firefox | 74.0.1-r0 | — |
| Alpine v3.18 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.18 | thunderbird | 68.7.0-r0 | — |
| Alpine v3.17 | firefox | 74.0.1-r0 | — |
| Alpine v3.17 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.17 | thunderbird | 68.7.0-r0 | — |
| Alpine v3.16 | firefox | 74.0.1-r0 | — |
| Alpine v3.16 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.16 | thunderbird | 68.7.0-r0 | — |
| Alpine v3.15 | firefox | 74.0.1-r0 | — |
| Alpine v3.15 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.14 | firefox | 74.0.1-r0 | — |
| Alpine v3.14 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.13 | firefox | 74.0.1-r0 | — |
| Alpine v3.13 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.12 | firefox | 74.0.1-r0 | — |
| Alpine v3.12 | firefox-esr | 68.6.1-r0 | — |
| Alpine v3.12 | mozjs68 | 68.7.0-r0 | — |
| Alpine v3.11 | firefox-esr | 68.6.1-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 68.8.0-1.amzn2 | ALAS2-2020-1429 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | firefox | 68.6.1-1.0.1.el8_1 | ELSA-2020-1341 |
| Oracle Linux 8 | thunderbird | 68.7.0-1.0.1.el8_1 | ELSA-2020-1495 |
| Oracle Linux 7 | firefox | 68.6.1-1.0.1.el7_8 | ELSA-2020-1338 |
| Oracle Linux 7 | thunderbird | 68.7.0-1.0.1.el7_8 | ELSA-2020-1489 |
Advisories 30
- RHSA-2020:1489 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:1488 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:1338 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:1339 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-4328-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-4335-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-4317-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4656-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2172-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2170-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-4653-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2020:0544-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0520-1 Security update for MozillaThunderbird 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-2020:0461-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0929-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14337-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0928-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:1027-1 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
- RHSA-2020:1495 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:1496 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:1341 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:1340 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- openSUSE-SU-2024:10601-1 MozillaThunderbird-91.1.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- ALAS2-2020-1429 Critical: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · May 20, 2020
- ELSA-2020-1495 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 18, 2020
- ELSA-2020-1489 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 17, 2020
- ELSA-2020-1338 Critical: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 11, 2020
- ELSA-2020-1341 Critical: firefox security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 9, 2020