CVE-2026-109740
published 2026-10-13CVE-2026-109740: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird…
PriorityP425high8.8
EPSS
0.16%
4.6th percentile
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.
Affected
5 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 158 | Firefox 158 |
| mozilla | firefox | — | — |
| mozilla | firefox_esr | < Firefox ESR 153.5 | Firefox ESR 153.5 |
| mozilla | thunderbird | < Thunderbird 153.5 | Thunderbird 153.5 |
| mozilla | thunderbird | < Thunderbird 158 | Thunderbird 158 |
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Red Hat
firefox: firefox: Sandbox escape via incorrect boundary conditions in Win32 widget
vendor_redhat·2026-10-13·CVSS 8.8
CVE-2026-109740 [HIGH] CWE-653 firefox: firefox: Sandbox escape via incorrect boundary conditions in Win32 widget
firefox: firefox: Sandbox escape via incorrect boundary conditions in Win32 widget
A flaw was found in Firefox. Incorrect boundary condition handling in the Win32 widget component allows an attacker to escape the browser's restricted sandbox environment. An attacker who has compromised a sandboxed content process could exploit this vulnerability to achieve privilege escalation and execute arbitrary code on the underlying operating system.
Package: firefox (Red Hat Enterprise Linux 10) - Will not fix
Package: firefox (Red Hat Enterprise Linux 7) - Will not fix
Package: firefox (Red Hat Enterprise Linux 8) - Will not fix
Package: firefox (Red Hat Enterprise Linux 9) - Will not fix
Mozilla
Mozilla Foundation Security Advisory 2026-106: CVE-2026-109740
vendor_mozilla
CVE-2026-109740 Mozilla Foundation Security Advisory 2026-106: CVE-2026-109740
Mozilla Foundation Security Advisory 2026-106
CVE: CVE-2026-109740
Product: Firefox
Impact: low
Fixed in: Firefox 158
Mozilla
Mozilla Foundation Security Advisory 2026-110: CVE-2026-109740
vendor_mozilla
CVE-2026-109740 Mozilla Foundation Security Advisory 2026-110: CVE-2026-109740
Mozilla Foundation Security Advisory 2026-110
CVE: CVE-2026-109740
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 153.5
Mozilla
Mozilla Foundation Security Advisory 2026-108: CVE-2026-109740
vendor_mozilla
CVE-2026-109740 Mozilla Foundation Security Advisory 2026-108: CVE-2026-109740
Mozilla Foundation Security Advisory 2026-108
CVE: CVE-2026-109740
Product: Firefox ESR
Impact: low
Fixed in: Firefox ESR 153.5
Mozilla
Mozilla Foundation Security Advisory 2026-109: CVE-2026-109740
vendor_mozilla
CVE-2026-109740 Mozilla Foundation Security Advisory 2026-109: CVE-2026-109740
Mozilla Foundation Security Advisory 2026-109
CVE: CVE-2026-109740
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 158
GHSA
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component.
ghsa_unreviewed·2026-10-13
CVE-2026-109740 Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component.
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.
No detection rules found.
No public exploits indexed.
2026-10-13
Published