CVE-2026-0891

Published Jan 13, 2026

Last updated 8 days ago

Overview

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 was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
Source
security@mozilla.org
NVD status
Modified
Products
firefox, thunderbird

Risk scores

CVSS 3.1

Type
Secondary
Base score
8.1
Impact score
5.9
Exploitability score
2.2
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-119

Social media

Hype score
Not currently trending

Configurations

References

Sources include official advisories and independent security research.