VDB
CVE-2026-109740
CVE-2026-109740
PUBLISHED
CVSS 9.6 CRITICAL
Reported by mozilla · Published October 13, 2026
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Risk Scores
CVSS 3.1
9.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | 153.5, 158 |
| Mozilla | Thunderbird | 153.5, 158 |
| Mozilla | Firefox | 153.5, 158 |
| Mozilla | Thunderbird | 153.5, 158 |
| chainguard | firefox-esr-140 | 0 |
Timeline
- Oct 13, 2026 Coalition ESS Score
- Oct 13, 2026 CVE Published
- Oct 14, 2026 EPSS Score
- Oct 19, 2026 CVE Updated
- Oct 20, 2026 EPSS Score
- Oct 21, 2026 EPSS Score
- Oct 23, 2026 EPSS Score
- Oct 25, 2026 EPSS Score
- Oct 29, 2026 EPSS Score