CVE-2025-11721
Critical
Description
Memory safety bug present in Firefox 143 and Thunderbird 143. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 144 and Thunderbird 144.
SeverityCritical
CVSS9.8
Exploit probability—
Product
Mozilla Firefox
PublishedOct 14, 2025
First seenOct 14, 2025
Weakness typeCWE-119Memory buffer bounds error
How to fix
Update
- mozilla firefox144.0 or later
- mozilla thunderbird144.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | 143.0 ≤ v < 144.0 | 144.0 |
| mozilla thunderbird | 143.0 ≤ v < 144.0 | 144.0 |
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