9.8
Critical
CVE-2025-11721 Memory safety bug present in Firefox 143 and Thunderbird 143
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Firefox 144 | earliest → < 144 | 144 |
| Thunderbird 144 | earliest → < 144 | 144 |