CVE-2026-84142

Mozilla · Published September 1, 2026

9.8

CVSS v3.1

CRITICAL

Patch availableGet patch

Description

Internally found bugs present in Thunderbird 154. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

Affected Products

Firefox < 155.0.0
Thunderbird < 155.0

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H