CVE-2026-8949
High
Description
Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Mozilla Firefox
PublishedMay 19, 2026
First seenMay 19, 2026
Weakness typeCWE-190Integer overflow
How to fix
Update
- mozilla firefox140.11.0, 151.0.0 or later
- mozilla thunderbird140.11, 151.0.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 140.11.0, v < 151.0.0 | 140.11.0, 151.0.0 |
| mozilla thunderbird | v < 140.11, v < 151.0.0 | 140.11, 151.0.0 |
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