Description
Firefox behaved slightly differently for already known resources when loading CSS resources involving CSS variables. This could have been used to probe the browser history. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | unspecified – < 91.9 | 91.9 |
| Mozilla | Firefox ESR | unspecified – < 91.9 | 91.9 |
| Mozilla | Firefox | unspecified – < 100 | 100 |
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 | 91.9.0esr-1 | — |
| Debian 14 | thunderbird | 1:91.9.0-1 | — |
| Debian 13 | firefox-esr | 91.9.0esr-1 | — |
| Debian 13 | thunderbird | 1:91.9.0-1 | — |
| Debian 12 | firefox-esr | 91.9.0esr-1 | — |
| Debian 12 | thunderbird | 1:91.9.0-1 | — |
| Debian 11 | firefox-esr | 91.9.0esr-1~deb11u1 | DSA-5129-1 |
| Debian 11 | thunderbird | 1:91.9.0-1~deb11u1 | DSA-5141-1 |
| Debian 10 | firefox-esr | 91.9.0esr-1~deb10u1 | DSA-5129-1 |
| Debian 10 | thunderbird | 1:91.9.0-1~deb10u1 | DSA-5141-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 9 | firefox-esr | 91.9.0esr-1~deb9u1 | DLA-2994-1 |
| Debian 9 | thunderbird | 1:91.9.0-1~deb9u1 | DLA-3020-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | mozjs78 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | thunderbird | 1:91.9.1+build1-0ubuntu0.22.04.1 | USN-5435-1 |
| Ubuntu 20.04 LTS | firefox | 100.0+build2-0ubuntu0.20.04.1 | USN-5411-1 |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 20.04 LTS | thunderbird | 1:91.9.1+build1-0ubuntu0.20.04.1 | USN-5435-1 |
| Ubuntu 18.04 LTS | firefox | 100.0+build2-0ubuntu0.18.04.1 | USN-5411-1 |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | thunderbird | 1:91.9.1+build1-0ubuntu0.18.04.1 | USN-5435-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | firefox | 91.9.0-1.el9_0 | RHSA-2022:4590 |
| RHEL 9 | thunderbird | 91.9.0-3.el9_0 | RHSA-2022:4589 |
| RHEL 8 | firefox | 91.9.0-1.el8_5 | RHSA-2022:1705 |
| RHEL 8 | thunderbird | 91.9.0-3.el8_5 | RHSA-2022:1730 |
| RHEL 7 | firefox | 91.9.0-1.el7_9 | RHSA-2022:1703 |
| RHEL 7 | thunderbird | 91.9.0-3.el7_9 | RHSA-2022:1725 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.4 EUS | firefox | 91.9.0-1.el8_4 | RHSA-2022:1702 |
| RHEL 8.4 EUS | thunderbird | 91.9.0-3.el8_4 | RHSA-2022:1726 |
| RHEL 8.2 EUS | firefox | 91.9.0-1.el8_2 | RHSA-2022:1704 |
| RHEL 8.2 EUS | thunderbird | 91.9.0-3.el8_2 | RHSA-2022:1724 |
| RHEL 8.1 E4S | firefox | 91.9.0-1.el8_1 | RHSA-2022:1701 |
| RHEL 8.1 E4S | thunderbird | 91.9.0-3.el8_1 | RHSA-2022:1727 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | firefox | 91.9.0-1.el8_5.alma | ALSA-2022:1705 |
| AlmaLinux 8 | thunderbird | 91.9.0-3.el8_5.alma | ALSA-2022:1730 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | firefox | 91.9.0-1.el8_5 | RLSA-2022:1705 |
| Rocky Linux 8 | thunderbird | 91.9.0-3.el8_5 | RLSA-2022:1730 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP4 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SLES 15 SP4 | MozillaThunderbird | 91.9.0-150200.8.68.2 | SUSE-SU-2022:1719-1 |
| SLES 15 SP3 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SLES 15 SP3 | MozillaThunderbird | 91.9.0-150200.8.68.2 | SUSE-SU-2022:1719-1 |
| SLES 15 SP2 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SLES 15 SP1 | MozillaFirefox | 91.9.0-150000.150.38.3 | SUSE-SU-2022:1731-1 |
| SLES 15 | MozillaFirefox | 91.9.0-150000.150.38.3 | SUSE-SU-2022:1731-1 |
Show 23 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SLES 12 SP4 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SLES 12 SP3 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SLES 12 SP2 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SLES for SAP 15 SP2 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SLES for SAP 15 SP1 | MozillaFirefox | 91.9.0-150000.150.38.3 | SUSE-SU-2022:1731-1 |
| SLES for SAP 15 | MozillaFirefox | 91.9.0-150000.150.38.3 | SUSE-SU-2022:1731-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SLE HPC 15 SP2 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SLE HPC 15 SP1 | MozillaFirefox | 91.9.0-150000.150.38.3 | SUSE-SU-2022:1731-1 |
| SLE HPC 15 | MozillaFirefox | 91.9.0-150000.150.38.3 | SUSE-SU-2022:1731-1 |
| SUSE OpenStack Cloud Crowbar 9 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SUSE OpenStack Cloud 9 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SUSE Manager Server 4.1 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SUSE Manager Retail Branch Server 4.1 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SUSE Manager Proxy 4.1 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 91.9.0-112.108.4 | SUSE-SU-2022:1757-1 |
| SUSE Enterprise Storage 7 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| SUSE Enterprise Storage 6 | MozillaFirefox | 91.9.0-150000.150.38.3 | SUSE-SU-2022:1731-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 100.0-1.1 | openSUSE-SU-2024:12044-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 91.9.0-1.1 | openSUSE-SU-2024:12045-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
| openSUSE Leap 15.4 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| openSUSE Leap 15.4 | MozillaThunderbird | 91.9.0-150200.8.68.2 | SUSE-SU-2022:1719-1 |
| openSUSE Leap 15.3 | MozillaFirefox | 91.9.0-150200.152.33.1 | SUSE-SU-2022:1748-1, SUSE-RU-2022:1579-1 |
| openSUSE Leap 15.3 | MozillaThunderbird | 91.9.0-150200.8.68.2 | SUSE-SU-2022:1719-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | librewolf | 100.0-r0 | — |
| Alpine v3.23 | firefox +1 | 100.0-r0 | — |
| Alpine v3.23 | firefox-esr +1 | 91.9.0-r0 | — |
| Alpine v3.22 | firefox +1 | 100.0-r0 | — |
| Alpine v3.22 | firefox-esr +1 | 91.9.0-r0 | — |
| Alpine v3.21 | firefox +1 | 100.0-r0 | — |
| Alpine v3.21 | firefox-esr +1 | 91.9.0-r0 | — |
| Alpine v3.20 | firefox | 100.0-r0 | — |
| Alpine v3.20 | firefox-esr +1 | 91.9.0-r0 | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | firefox | 100.0-r0 | — |
| Alpine v3.19 | firefox-esr +1 | 91.9.0-r0 | — |
| Alpine v3.18 | firefox | 100.0-r0 | — |
| Alpine v3.18 | firefox-esr +1 | 91.9.0-r0 | — |
| Alpine v3.17 | firefox | 100.0-r0 | — |
| Alpine v3.17 | firefox-esr +1 | 91.9.0-r0 | — |
| Alpine v3.16 | firefox | 100.0-r0 | — |
| Alpine v3.16 | firefox-esr +1 | 91.9.0-r0 | — |
| Alpine v3.15 | firefox-esr | 91.9.0-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | firefox | 91.9.0-1.0.1.el9_0 | ELSA-2022-4590 |
| Oracle Linux 9 | thunderbird | 91.9.0-3.0.1.el9_0 | ELSA-2022-4589 |
| Oracle Linux 8 | firefox | 91.9.0-1.0.1.el8_5 | ELSA-2022-1705 |
| Oracle Linux 8 | thunderbird | 91.9.0-3.0.1.el8_5 | ELSA-2022-1730 |
| Oracle Linux 7 | firefox | 91.9.0-1.0.1.el7_9 | ELSA-2022-1703 |
| Oracle Linux 7 | thunderbird | 91.9.0-3.0.1.el7_9 | ELSA-2022-1725 |
Advisories 39
- ALSA-2022:1705 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2022:1730 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2022:1725 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2022:1703 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-5435-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-5411-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-5141-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-5129-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3020-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2994-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2022:1730 Important: thunderbird security update Rocky Linux Security Advisories · Feb 5, 2026
- RLSA-2022:1705 Important: firefox security update Rocky Linux Security Advisories · Feb 5, 2026
- SUSE-RU-2022:1579-1 Recommended update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:12045-1 MozillaThunderbird-91.9.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:1731-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:1757-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:1748-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:1719-1 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-2022:4590 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:4589 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1730 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1727 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1726 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1724 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1705 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1704 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1701 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:1702 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- WID-SEC-2022-1335 Xerox FreeFlow Print Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 6, 2025
- openSUSE-SU-2024:12044-1 MozillaFirefox-100.0-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- WID-SEC-2022-0537 Mozilla Firefox und Mozilla Firefox ESR: Mehrere Schwachstellen BSI CERT-Bund (WID) · Apr 1, 2025
- WID-SEC-2022-0538 Mozilla Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Apr 1, 2025
- ELSA-2022-4590 Important: firefox security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 30, 2022
- ELSA-2022-4589 Important: thunderbird security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 30, 2022
- ELSA-2022-1730 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 5, 2022
- ELSA-2022-1725 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · May 5, 2022
- ELSA-2022-1705 Important: firefox security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 4, 2022
- ELSA-2022-1703 Important: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · May 4, 2022