CVE-2026-4371

Published Mar 24, 2026

Last updated 11 hours ago

Overview

Description
A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability affects Thunderbird < 149 and Thunderbird < 140.9.
Source
security@mozilla.org
NVD status
Analyzed
Products
thunderbird

Risk scores

CVSS 3.1

Type
Secondary
Base score
7.4
Impact score
5.2
Exploitability score
2.2
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H
Severity
HIGH

Weaknesses

134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-126

Social media

Hype score
Not currently trending

Configurations