CVE-2025-4919
High
Description
An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability was fixed in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.
SeverityHigh
CVSS8.8
Exploit probability—
Product
Mozilla Firefox
PublishedMay 17, 2025
First seenMay 17, 2025
Weakness typeCWE-125Out-of-bounds readCWE-787Out-of-bounds write
How to fix
Update
- mozilla firefox115.23.1, 138.0.4, 128.10.1 or later
- mozilla thunderbird128.10.2, 138.0.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 115.23.1, v < 138.0.4, 116.0 ≤ v < 128.10.1 | 115.23.1, 138.0.4, 128.10.1 |
| mozilla thunderbird | v < 128.10.2, 138.0 ≤ v < 138.0.2 | 128.10.2, 138.0.2 |
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