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OpenAdvisories
Critical · 9.6 CVE-2026-100778 EUVD-2026-88930GHSA-jm26-3479-fr7j

Sandbox escape due to use-after-free in the DOM: Core & HTML component

Published Sep 29, 2026 · Updated Sep 30, 2026 · Assigned by mozilla

Description

Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

Affected products

VendorProductAffectedFixed
Mozilla Firefox — 115.42
Mozilla Thunderbird — 140.17

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.

ReleasePackageFixed inAdvisory
Debian 14 firefox-esr 153.4.0esr-1 —
Debian 14 thunderbird 1:153.4.0esr-1 —
Debian 13 firefox-esr 153.4.0esr-1~deb13u1 —
Debian 13 thunderbird 1:140.17.0esr-1~deb13u1 —
Debian 12 firefox-esr 153.4.0esr-1~deb12u1 —
Debian 12 thunderbird 1:140.17.0esr-1~deb12u1 —
ReleasePackageFixed inAdvisory
Ubuntu 24.04 LTS mozjs102 +1 No fix yet —
Ubuntu 22.04 LTS mozjs78 +3 No fix yet —
Ubuntu 20.04 LTS mozjs52 +1 No fix yet —
Ubuntu 18.04 LTS mozjs38 +1 No fix yet —
ReleasePackageFixed inAdvisory
RHEL 10 firefox +1 140.17.0-1.el10_2 RHSA-2026:80674, RHSA-2026:76764
RHEL 9 firefox +2 140.17.0-1.el9_8 RHSA-2026:80694, RHSA-2026:76761
RHEL 8 firefox +1 140.17.0-1.el8_10 RHSA-2026:90913, RHSA-2026:76850
Show 11 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
RHEL 10.0 EUS firefox +1 140.17.0-1.el10_0 RHSA-2026:92227, RHSA-2026:85240
RHEL 9.6 EUS firefox +2 140.17.0-1.el9_6 RHSA-2026:92335, RHSA-2026:85244
RHEL 9.4 E4S firefox +2 140.17.0-1.el9_4 RHSA-2026:92012, RHSA-2026:85241
RHEL 9.2 E4S firefox +2 140.17.0-1.el9_2 RHSA-2026:92226, RHSA-2026:85242
RHEL 8.8 TUS firefox +1 140.17.0-1.el8_8 RHSA-2026:92327, RHSA-2026:91633
RHEL 8.8 E4S firefox +1 140.17.0-1.el8_8 RHSA-2026:92327, RHSA-2026:91633
RHEL 8.6 EUS Long Life firefox +1 140.17.0-1.el8_6 RHSA-2026:92228, RHSA-2026:91634
RHEL 8.6 AUS firefox +1 140.17.0-1.el8_6 RHSA-2026:92228, RHSA-2026:91634
RHEL 8.4 EUS Long Life firefox +1 140.17.0-1.el8_4 RHSA-2026:92011, RHSA-2026:85243
RHEL 8.4 AUS firefox +1 140.17.0-1.el8_4 RHSA-2026:92011, RHSA-2026:85243
RHEL 7 ELS firefox 140.17.0-1.el7_9 RHSA-2026:92363

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 10 firefox 140.17.0-1.el10_2 ALSA-2026:76764
AlmaLinux 10 thunderbird 140.17.0-1.el10_2.alma.1 ALSA-2026:80674
AlmaLinux 9 firefox +2 140.17.0-1.el9_8.alma.1 ALSA-2026:80694, ALSA-2026:76761
AlmaLinux 8 firefox +1 140.17.0-1.el8_10.alma.1 ALSA-2026:90913, ALSA-2026:76850

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 10 firefox +1 140.17.0-1.el10_2 RLSA-2026:80674, RLSA-2026:76764
Rocky Linux 9 firefox +1 140.17.0-1.el9_8 RLSA-2026:80694, RLSA-2026:76761
Rocky Linux 8 firefox +1 140.17.0-1.el8_10 RLSA-2026:90913, RLSA-2026:76850
ReleasePackageFixed inAdvisory
SLES 15 SP7 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLES 15 SP7 MozillaThunderbird 153.4.0-150400.13.6.1 SUSE-SU-2026:4627-1
SLES 15 SP6 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLES 15 SP5 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLES 15 SP4 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLES 12 SP5 MozillaFirefox 153.4.0-118.11.1 SUSE-SU-2026:4543-1
Show 7 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 MozillaFirefox 153.4.0-160000.1.1 SUSE-SU-2026:23981-1
SLES for SAP 15 SP6 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLES for SAP 15 SP5 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLES for SAP 15 SP4 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLES 16.0 MozillaFirefox 153.4.0-160000.1.1 SUSE-SU-2026:23981-1
SLE HPC 15 SP5 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
SLE HPC 15 SP4 MozillaFirefox 153.4.0-150400.157.11.1 SUSE-SU-2026:4545-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed MozillaFirefox 157.0.1-1.1 openSUSE-SU-2026:12097-1
openSUSE Tumbleweed firefox-esr +1 153.4.0-1.1 openSUSE-SU-2026:12098-1, openSUSE-SU-2026:11917-1
openSUSE Leap 16.0 MozillaFirefox 153.4.0-160000.1.1 openSUSE-SU-2026:21980-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 firefox 140.17.0-1.amzn2023.0.1 ALAS2023-2026-3214
Amazon Linux 2 thunderbird 153.5.1-1.amzn2.0.1 ALAS2-2026-4057

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 10 firefox +1 140.17.0-1.0.1.el10_2 ELSA-2026-80674, ELSA-2026-76764
Oracle Linux 9 firefox +2 140.17.0-1.0.1.el9_8 ELSA-2026-80694, ELSA-2026-76761
Oracle Linux 8 firefox +1 140.17.0-1.0.1.el8_10 ELSA-2026-90913, ELSA-2026-76850
Oracle Linux 7 firefox 140.17.0-1.0.1.el7_9 ELSA-2026-92363

Advisories 50

References