CVE-2026-84143

Published Sep 1, 2026

Last updated 7 days ago

Overview

Description
Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. 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, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Source
security@mozilla.org
NVD status
Modified
Products
firefox, thunderbird

Risk scores

CVSS 3.1

Type
Primary
Base score
9.8
Impact score
5.9
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity
CRITICAL

Weaknesses

nvd@nist.gov
CWE-119
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-200

Social media

Hype score
Not currently trending

Configurations