9.8
Critical
CVE-2026-74989 Internally found bugs present in Firefox 153
Description
Internally found bugs present in Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154 and Thunderbird 154.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Firefox 154 | earliest → < 154 | 154 |
| Thunderbird 154 | earliest → < 154 | 154 |