CVE-2026-4723
Critical
Description
Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.
SeverityCritical
CVSS9.8
Exploit probability—
Product
Mozilla Firefox
PublishedMar 24, 2026
First seenMar 24, 2026
Weakness typeCWE-416Use after free
How to fix
Update
- mozilla firefox149.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 149.0 | 149.0 |
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