Use-after-free in Mozilla products - CVE-2026-2786

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Main Vulnerability Database Vulnerabilities #VU123212

Use-after-free in Mozilla products - CVE-2026-2786

Published: February 24, 2026


Vulnerability identifier: #VU123212
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-2786
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to crash the browser.

The vulnerability exists due to a use-after-free error in the JavaScript Engine component. A remote attacker can trick the victim into visiting a specially crafted website and crash the browser. 


Affected software

Mozilla Firefox
Firefox ESR
Firefox for Android
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 15 SP4
Debian Linux
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Workstation Extension 15
Anolis OS
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
SUSE Package Hub 15
Desktop Applications Module
openSUSE Leap
openEuler
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
firefox-esr (Debian package)
thunderbird (Debian package)
firefox-debugsource
firefox-debuginfo
firefox
thunderbird-debugsource
thunderbird-debuginfo
thunderbird
thunderbird-wayland
thunderbird-librnp-rnp
thunderbird (Red Hat package)
firefox (Red Hat package)
MozillaFirefox-debuginfo
MozillaFirefox-debugsource
MozillaFirefox-translations-common
MozillaFirefox-devel
MozillaFirefox
MozillaThunderbird
MozillaThunderbird-translations-common
MozillaThunderbird-debuginfo
MozillaThunderbird-translations-other
MozillaThunderbird-debugsource
MozillaFirefox-branding-upstream
MozillaFirefox-translations-other
Mozilla Thunderbird

How to mitigate CVE-2026-2786

Install updates from vendor's website.

Mozilla Firefox - update to 148.0
Firefox ESR - update to 140.8.0
Firefox for Android - update to 148.0
Mozilla Thunderbird - addressed in versions 140.8.0, 148.0
firefox-esr (Debian package) - addressed in versions 140.8.0esr-1~deb12u1, 140.8.0esr-1~deb13u1
thunderbird (Debian package) - addressed in versions 1:140.8.0esr-1~deb12u1, 1:140.8.0esr-1~deb13u1
firefox-debugsource - update to 140.8.0-1
firefox-debuginfo - update to 140.8.0-1
firefox - update to 140.8.0-1
thunderbird-debugsource - update to 140.8.0-1
thunderbird-debuginfo - update to 140.8.0-1
thunderbird - update to 140.8.0-1
thunderbird-wayland - update to 140.8.0-1
thunderbird-librnp-rnp - update to 140.8.0-1
thunderbird (Red Hat package) - addressed in versions 140.8.0-1.el8_2, 140.8.0-1.el8_6, 140.8.0-1.el8_8, 140.8.0-1.el9_0, 140.8.0-1.el9_2, 140.8.0-1.el9_6, 140.8.0-1.el9_7, 140.8.0-2.el10_0, 140.8.0-2.el10_1
firefox (Red Hat package) - addressed in versions 140.8.0-2.el7_9, 140.8.0-2.el8_2, 140.8.0-2.el8_4, 140.8.0-2.el8_6, 140.8.0-2.el8_8, 140.8.0-2.el9_0, 140.8.0-2.el9_2, 140.8.0-2.el9_4, 140.8.0-2.el9_6, 140.8.0-2.el9_7, 140.8.0-2.el10_1
firefox - update to 140.8.0-2.0.1
MozillaFirefox-debuginfo - addressed in versions 140.8.0-112.301.1, 140.8.0-150200.152.222.1
MozillaFirefox-debugsource - addressed in versions 140.8.0-112.301.1, 140.8.0-150200.152.222.1
MozillaFirefox-translations-common - addressed in versions 140.8.0-112.301.1, 140.8.0-150200.152.222.1
MozillaFirefox-devel - addressed in versions 140.8.0-112.301.1, 140.8.0-150200.152.222.1
MozillaFirefox - addressed in versions 140.8.0-112.301.1, 140.8.0-150200.152.222.1
MozillaThunderbird - update to 140.8.0-150200.8.260.1
MozillaThunderbird-translations-common - update to 140.8.0-150200.8.260.1
MozillaThunderbird-debuginfo - update to 140.8.0-150200.8.260.1
MozillaThunderbird-translations-other - update to 140.8.0-150200.8.260.1
MozillaThunderbird-debugsource - update to 140.8.0-150200.8.260.1
MozillaFirefox-branding-upstream - update to 140.8.0-150200.152.222.1
MozillaFirefox-translations-other - update to 140.8.0-150200.152.222.1
thunderbird - update to 140.12.0-1.0.1

External References

Related Security Bulletins