CVE-2026-109707
Critical
Description
Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.
SeverityCritical
CVSS9.6
Exploit probability—
Product
Firefox
PublishedOct 13, 2026
First seenOct 13, 2026
Weakness typeCWE-416Use after free
How to fix
Update
- Mozilla Firefox158 or later
- Mozilla Firefox ESR153.5, 115.44 or later
- Mozilla Thunderbird158, 153.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Mozilla Firefox | No range specified | 158 |
| Mozilla Firefox ESR | No range specified | 153.5, 115.44 |
| Mozilla Thunderbird | No range specified | 158, 153.5 |
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