CVE-2026-109740

CVSS 9.6 (critical) · published 2026-10-13

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.

Weakness: CWE-119

Source: NVD CVE-2026-109740

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2057113
• https://www.mozilla.org/security/advisories/mfsa2026-106/
• https://www.mozilla.org/security/advisories/mfsa2026-108/
• https://www.mozilla.org/security/advisories/mfsa2026-109/
• https://www.mozilla.org/security/advisories/mfsa2026-110/

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