CVE-2025-4091
High
Description
Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. 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 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbird 128.10.
SeverityHigh
CVSS8.1
Exploit probability—
Product
Mozilla Firefox
PublishedApr 29, 2025
First seenApr 29, 2025
Weakness typeCWE-119Memory buffer bounds error
How to fix
Update
- mozilla firefox128.10, 138.0 or later
- mozilla thunderbird128.10.0, 138.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 128.10, v < 138.0 | 128.10, 138.0 |
| mozilla thunderbird | v < 128.10.0, v < 138.0 | 128.10.0, 138.0 |
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