Buffer overflow in Mozilla products - CVE-2026-12329

Vulnerability identifier: #VU134619

CSH Severity: High

CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber

CVE-ID: CVE-2026-12329

CWE-ID: CWE-119

Exploitation vector: Remote access

Exploit availability: No public exploit available

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

The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to execute arbitrary code.

Install security update from vendor's website.

• https://www.mozilla.org/en-US/security/advisories/mfsa2026-58/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-57/
• https://bugzilla.mozilla.org/show_bug.cgi?id=2044738