CVE-2026-118021
High
Description
Sandbox escape due to use-after-free in the XPCOM component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.
SeverityHigh
CVSS8.8
Exploit probability—
ProductFirefox
PublishedOct 27, 2026
First seenOct 27, 2026
Weakness typeCWE-416Use after free
How to fix
Update
- Firefox159 or later
- Thunderbird159 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Firefox | No range specified | 159 |
| Thunderbird | No range specified | 159 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
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