CVE-2026-0891

HIGH

Mozilla Firefox < 140.7.0 - Memory Corruption

Title source: rule

Description

Memory safety bugs present in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 and Thunderbird 146. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.

Scores

CVSS v3 8.1
EPSS 0.0002
EPSS Percentile 6.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Classification

CWE
CWE-119
Status published

Affected Products (4)

mozilla/firefox < 140.7.0
mozilla/firefox < 147.0
mozilla/thunderbird < 140.7.0
mozilla/thunderbird < 147.0

Timeline

Published Jan 13, 2026
Tracked Since Feb 18, 2026