CVE-2026-75874
Critical
Description
Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2.
SeverityCritical
CVSS10.0
Exploit probability40. percentile0.5%
Product
Mozilla Firefox
PublishedAug 18, 2026
First seenAug 18, 2026
Weakness typeCWE-693CWE-693
How to fix
Update
- mozilla firefox154.0.0 or later
- mozilla thunderbird154.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 154.0.0 | 154.0.0 |
| mozilla thunderbird | v < 154.0 | 154.0 |
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