Description
Memory safety bugs present in Firefox 120, Firefox ESR 115.5, and Thunderbird 115.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 115.6, Thunderbird < 115.6, and Firefox < 121.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox ESR | unspecified – < 115.6 | 115.6 |
| Mozilla | Thunderbird | unspecified – < 115.6 | 115.6 |
| Mozilla | Firefox | unspecified – < 121 | 121 |
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 | 115.6.0esr-1 | — |
| Debian 14 | thunderbird | 1:115.6.0-1 | — |
| Debian 13 | firefox-esr | 115.6.0esr-1 | — |
| Debian 13 | thunderbird | 1:115.6.0-1 | — |
| Debian 12 | firefox-esr | 115.6.0esr-1~deb12u1 | DSA-5581-1 |
| Debian 12 | thunderbird | 1:115.6.0-1~deb12u1 | DSA-5582-1 |
| Debian 11 | firefox-esr | 115.6.0esr-1~deb11u1 | DSA-5581-1 |
| Debian 11 | thunderbird | 1:115.6.0-1~deb11u1 | DSA-5582-1 |
| Debian 10 | firefox-esr | 115.6.0esr-1~deb10u1 | DLA-3697-1 |
| Debian 10 | thunderbird | 1:115.6.0-1~deb10u1 | DLA-3698-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | mozjs102 | No fix yet | — |
| Ubuntu 24.04 LTS | thunderbird | 1:115.6.0+build2-0ubuntu1 | — |
| Ubuntu 22.04 LTS | mozjs78 +2 | No fix yet | — |
| Ubuntu 22.04 LTS | thunderbird | 1:115.6.0+build2-0ubuntu0.22.04.1 | USN-6563-1 |
| Ubuntu 20.04 LTS | firefox | 121.0+build1-0ubuntu0.20.04.1 | USN-6562-1 |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 20.04 LTS | thunderbird | 1:115.6.0+build2-0ubuntu0.20.04.1 | USN-6563-1 |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | firefox +2 | 115.6.0-1.el9_3 | RHSA-2024:0025, RHSA-2024:0001 |
| RHEL 8 | firefox +1 | 115.6.0-1.el8_9 | RHSA-2024:0012, RHSA-2024:0003 |
| RHEL 7 | firefox +1 | 115.6.0-1.el7_9 | RHSA-2024:0027, RHSA-2024:0026 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.2 EUS | firefox +2 | 115.6.0-1.el9_2 | RHSA-2024:0029, RHSA-2024:0019 |
| RHEL 9.0 EUS | firefox +1 | 115.6.0-1.el9_0 | RHSA-2024:0022, RHSA-2024:0002 |
| RHEL 8.8 EUS | firefox +1 | 115.6.0-1.el8_8 | RHSA-2024:0011, RHSA-2024:0004 |
| RHEL 8.6 EUS | firefox +1 | 115.6.0-1.el8_6 | RHSA-2024:0024, RHSA-2024:0005 |
| RHEL 8.4 TUS | firefox +1 | 115.6.0-1.el8_4 | RHSA-2024:0028, RHSA-2024:0021 |
| RHEL 8.4 E4S | firefox +1 | 115.6.0-1.el8_4 | RHSA-2024:0028, RHSA-2024:0021 |
| RHEL 8.4 AUS | firefox +1 | 115.6.0-1.el8_4 | RHSA-2024:0028, RHSA-2024:0021 |
| RHEL 8.2 TUS | firefox +1 | 115.6.0-1.el8_2 | RHSA-2024:0030, RHSA-2024:0023 |
| RHEL 8.2 E4S | firefox +1 | 115.6.0-1.el8_2 | RHSA-2024:0030, RHSA-2024:0023 |
| RHEL 8.2 AUS | firefox +1 | 115.6.0-1.el8_2 | RHSA-2024:0030, RHSA-2024:0023 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | firefox +2 | 115.6.0-1.el9_3.alma | ALSA-2024:0025, ALSA-2024:0001 |
| AlmaLinux 8 | firefox +1 | 115.6.0-1.el8_9.alma | ALSA-2024:0012, ALSA-2024:0003 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | firefox +1 | 115.6.0-1.el8_9 | RLSA-2024:0012, RLSA-2024:0003 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLES 15 SP5 | MozillaThunderbird | 115.6.0-150200.8.142.2 | SUSE-SU-2024:0044-1 |
| SLES 15 SP4 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLES 15 SP3 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLES 15 SP2 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLES 15 SP1 | MozillaFirefox | 115.6.0-150000.150.119.1 | SUSE-SU-2023:4929-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | MozillaFirefox | 115.6.0-112.194.1 | SUSE-SU-2023:4912-1 |
| SLES for SAP 15 SP4 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLES for SAP 15 SP3 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLES for SAP 15 SP2 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLES for SAP 15 SP1 | MozillaFirefox | 115.6.0-150000.150.119.1 | SUSE-SU-2023:4929-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 115.6.0-112.194.1 | SUSE-SU-2023:4912-1 |
| SLE Real Time 15 SP4 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLE HPC 15 SP4 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLE HPC 15 SP3 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLE HPC 15 SP2 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| SLE HPC 15 SP1 | MozillaFirefox | 115.6.0-150000.150.119.1 | SUSE-SU-2023:4929-1 |
| SUSE Enterprise Storage 7.1 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 121.0-1.1 | openSUSE-SU-2024:13531-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 115.6.0-1.1 | openSUSE-SU-2024:13519-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
| openSUSE Leap 15.5 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
| openSUSE Leap 15.5 | MozillaThunderbird | 115.6.0-150200.8.142.2 | SUSE-SU-2024:0044-1 |
| openSUSE Leap 15.4 | MozillaFirefox | 115.6.0-150200.152.120.1 | SUSE-SU-2023:4928-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | mozjs | 115.6.0-r0 | — |
| Alpine v3.23 | mozjs +1 | 115.6.0-r0 | — |
| Alpine v3.22 | mozjs +1 | 115.6.0-r0 | — |
| Alpine v3.21 | mozjs +1 | 115.6.0-r0 | — |
| Alpine v3.20 | mozjs115 +1 | 115.6.0-r0 | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | mozjs115 +1 | 115.6.0-r0 | — |
| Alpine v3.18 | firefox-esr | 115.6.0-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 115.6.0-1.amzn2.0.1 | ALAS2-2024-2377 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | firefox +2 | 115.6.0-1.0.1.el9_3 | ELSA-2024-0025, ELSA-2024-0001 |
| Oracle Linux 8 | firefox +1 | 115.6.0-1.0.1.el8_9 | ELSA-2024-0012, ELSA-2024-0003 |
| Oracle Linux 7 | firefox +1 | 115.6.0-1.0.1.el7_9 | ELSA-2024-0027, ELSA-2024-0026 |
Advisories 46
- ALSA-2024:0025 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2024:0001 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2024:0003 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2024:0012 Important: firefox security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2024:0026 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2024:0027 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-6562-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-6563-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- RHSA-2024:0030 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0028 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0022 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0023 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0012 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0019 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0001 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0021 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0024 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0005 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0025 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0029 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0003 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0011 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0002 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- RHSA-2024:0004 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Mar 18, 2026
- DSA-5582-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-5581-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3698-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3697-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2024:0003 Important: thunderbird security update Rocky Linux Security Advisories · Feb 4, 2026
- RLSA-2024:0012 Important: firefox security update Rocky Linux Security Advisories · Feb 4, 2026
- SUSE-SU-2023:4912-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:13531-1 MozillaFirefox-121.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:4928-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:13519-1 MozillaThunderbird-115.6.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:4929-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:0044-1 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
- WID-SEC-2023-3185 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 2, 2025
- WID-SEC-2024-1248 Xerox FreeFlow Print Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 21, 2024
- ALAS2-2024-2377 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jan 9, 2024
- ELSA-2024-0001 Important: thunderbird security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jan 3, 2024
- ELSA-2024-0025 Important: firefox security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jan 3, 2024
- ELSA-2024-0012 Important: firefox security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 3, 2024
- ELSA-2024-0003 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 3, 2024
- ELSA-2024-0027 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 2, 2024
- ELSA-2024-0026 Important: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 2, 2024
References
- Memory safety bugs fixed in Firefox 121, Firefox ESR 115.6, and Thunderbird 115.6
- https://lists.debian.org/debian-lts-announce/2023/12/msg00020.html
- https://lists.debian.org/debian-lts-announce/2023/12/msg00021.html
- https://security.gentoo.org/glsa/202401-10
- https://www.debian.org/security/2023/dsa-5581
- https://www.debian.org/security/2023/dsa-5582
- https://www.mozilla.org/security/advisories/mfsa2023-54/
- https://www.mozilla.org/security/advisories/mfsa2023-55/
- https://www.mozilla.org/security/advisories/mfsa2023-56/