CVE-2026-103500
Medium
Description
An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.
SeverityMedium
CVSS6.1
Exploit probability—
Product
Mozilla Thunderbird
PublishedSep 30, 2026
First seenSep 30, 2026
Weakness typeCWE-122CWE-122
How to fix
Update
- mozilla thunderbird140.17.0, 153.4.0, 157.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla thunderbird | v < 140.17.0, 141.0 ≤ v < 153.4.0, 154.0 ≤ v < 157.0 | 140.17.0, 153.4.0, 157.0 |
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