Description
When recursing through graphical layers while scrolling, an iterator may have become invalid, resulting in a potential use-after-free. This occurs because the function APZCTreeManager::ComputeClippedCompositionBounds did not follow iterator invalidation rules. This vulnerability affects Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | unspecified – < 81 | 81 |
| Mozilla | Thunderbird | unspecified – < 78.3 | 78.3 |
| Mozilla | Firefox ESR | unspecified – < 78.3 | 78.3 |
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 | 78.3.0esr-1 | — |
| Debian 14 | thunderbird | 1:78.3.1-1 | — |
| Debian 13 | firefox-esr | 78.3.0esr-1 | — |
| Debian 13 | thunderbird | 1:78.3.1-1 | — |
| Debian 12 | firefox-esr | 78.3.0esr-1 | — |
| Debian 12 | thunderbird | 1:78.3.1-1 | — |
| Debian 10 | firefox-esr | 78.3.0esr-1~deb10u1 | DSA-4768-1 |
| Debian 10 | thunderbird | 1:78.3.1-2~deb10u2 | DSA-4770-1 |
| Debian 9 | firefox-esr | 78.3.0esr-1~deb9u1 | DLA-2387-1 |
| Debian 9 | thunderbird | 1:78.3.1-2~deb9u1 | DLA-2408-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | firefox | 81.0+build2-0ubuntu0.20.04.1 | USN-4546-1 |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | firefox | 81.0+build2-0ubuntu0.18.04.1 | USN-4546-1 |
| 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 | 81.0+build2-0ubuntu0.16.04.1 | USN-4546-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | firefox | 78.3.0-1.el8_2 | RHSA-2020:3832 |
| RHEL 8 | thunderbird | 78.3.1-1.el8_2 | RHSA-2020:4155 |
| RHEL 7 | firefox | 78.3.0-1.el7_9 | RHSA-2020:4080 |
| RHEL 7 | thunderbird | 78.3.1-1.el7_9 | RHSA-2020:4163 |
| RHEL 6 | firefox | 78.3.0-1.el6_10 | RHSA-2020:3835 |
| RHEL 6 | thunderbird | 78.3.1-1.el6_10 | RHSA-2020:4158 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.1 EUS | firefox | 78.3.0-1.el8_1 | RHSA-2020:3833 |
| RHEL 8.1 EUS | thunderbird | 78.3.1-1.el8_1 | RHSA-2020:4157 |
| RHEL 8.0 E4S | firefox | 78.3.0-1.el8_0 | RHSA-2020:3834 |
| RHEL 8.0 E4S | thunderbird | 78.3.1-1.el8_0 | RHSA-2020:4156 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | MozillaFirefox | 78.3.0-8.6.1 | SUSE-SU-2020:2749-1 |
| SLES 15 SP2 | MozillaThunderbird | 78.4.0-3.99.1 | SUSE-SU-2020:3091-1 |
| SLES 15 SP2 | mozilla-nspr | 4.25.1-3.15.2 | SUSE-SU-2020:3091-1 |
| SLES 15 SP1 | MozillaFirefox | 78.3.0-3.108.1 | SUSE-SU-2020:2747-1 |
| SLES 15 SP1 | MozillaThunderbird | 78.4.0-3.99.1 | SUSE-SU-2020:3091-1 |
| SLES 15 SP1 | mozilla-nspr | 4.25.1-3.15.2 | SUSE-SU-2020:3091-1 |
| SLES 12 SP5 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SLES 12 SP4 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SLES 12 SP3 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SLES 11 SP4 | MozillaFirefox | 78.3.0-78.93.1 | SUSE-SU-2020:14502-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SUSE OpenStack Cloud Crowbar 9 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SUSE OpenStack Cloud 9 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
| SUSE Enterprise Storage 5 | MozillaFirefox | 78.3.0-112.22.1 | SUSE-SU-2020:2759-1 |
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 | 78.3.0-lp152.2.21.1 | openSUSE-SU-2020:1574-1 |
| openSUSE Leap 15.2 | MozillaThunderbird | 78.4.0-lp152.2.13.1 | openSUSE-SU-2020:1780-1 |
| openSUSE Leap 15.2 | mozilla-nspr | 4.25.1-lp152.2.3.1 | openSUSE-SU-2020:1780-1 |
| openSUSE Leap 15.1 | MozillaFirefox | 78.3.0-lp151.2.69.1 | openSUSE-SU-2020:1555-1 |
| openSUSE Leap 15.1 | MozillaThunderbird | 78.4.0-lp151.2.53.1 | openSUSE-SU-2020:1785-1 |
| openSUSE Leap 15.1 | mozilla-nspr | 4.25.1-lp151.2.13.1 | openSUSE-SU-2020:1785-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | librewolf | 81.0-r0 | — |
| Alpine v3.23 | firefox +1 | 81.0-r0 | — |
| Alpine v3.23 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.22 | firefox +1 | 81.0-r0 | — |
| Alpine v3.22 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.21 | firefox +1 | 81.0-r0 | — |
| Alpine v3.21 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.20 | firefox | 81.0-r0 | — |
| Alpine v3.20 | firefox-esr | 78.3.0-r0 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | firefox | 81.0-r0 | — |
| Alpine v3.19 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.18 | firefox | 81.0-r0 | — |
| Alpine v3.18 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.17 | firefox | 81.0-r0 | — |
| Alpine v3.17 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.16 | firefox | 81.0-r0 | — |
| Alpine v3.16 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.15 | firefox | 81.0-r0 | — |
| Alpine v3.15 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.14 | firefox | 81.0-r0 | — |
| Alpine v3.14 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.13 | firefox | 81.0-r0 | — |
| Alpine v3.13 | firefox-esr | 78.3.0-r0 | — |
| Alpine v3.12 | firefox | 81.0-r0 | — |
| Alpine v3.12 | firefox-esr | 78.3.0-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 78.4.3-1.amzn2.0.1 | ALAS2-2020-1572 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | firefox | 78.3.0-1.0.1.el8_2 | ELSA-2020-3832 |
| Oracle Linux 8 | thunderbird | 78.3.1-1.0.1.el8_2 | ELSA-2020-4155 |
| Oracle Linux 7 | firefox | 78.3.0-1.0.1.el7_9 | ELSA-2020-4080 |
| Oracle Linux 7 | thunderbird | 78.3.1-1.0.1.el7_9 | ELSA-2020-4163 |
Advisories 32
- RHSA-2020:4163 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:4158 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:4080 Red Hat Security Advisory: firefox security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:3835 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-4546-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4770-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-4768-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2408-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2387-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2020:2759-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3091-1 Security update for MozillaThunderbird and mozilla-nspr SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14502-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1780-1 Security update for MozillaThunderbird and mozilla-nspr 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-2020:1574-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2749-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2747-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1555-1 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
- RHSA-2020:4157 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:4156 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:4155 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:3834 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:3833 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2020:3832 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- openSUSE-SU-2020:1785-1 Security update for MozillaThunderbird and mozilla-nspr 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
- ALAS2-2020-1572 Critical: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Dec 8, 2020
- ELSA-2020-4080 Important: firefox security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 13, 2020
- ELSA-2020-4163 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 13, 2020
- ELSA-2020-4155 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Oct 4, 2020
- ELSA-2020-3832 Important: firefox security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Sep 24, 2020
References
- https://www.mozilla.org/security/advisories/mfsa2020-43/
- https://www.mozilla.org/security/advisories/mfsa2020-44/
- https://www.mozilla.org/security/advisories/mfsa2020-42/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1660211
- DSA-4770 vendor-advisory
- [debian-lts-announce] 20201016 [SECURITY] [DLA 2408-1] thunderbird security update mailing-list
- GLSA-202010-02 vendor-advisory
- openSUSE-SU-2020:1780 vendor-advisory
- openSUSE-SU-2020:1785 vendor-advisory