{"id":"CVE-2026-109740","title":"Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component","summary":"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.","severity":"high","published":"2026-10-13","updated":"2026-10-13","sourceUpdated":"2026-10-13T19:18:38.053","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-109740","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2057113","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-106/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-108/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-109/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-110/","label":"security@mozilla.org"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-109740.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-109740"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2550404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-109740"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-109740"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-108/#CVE-2026-109740"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-110/#CVE-2026-109740"}],"tags":["nvd","csaf","vex","red-hat","cve.org","score-dispute"],"ingestedAt":"2026-10-13T13:27:04.003Z","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 7","enterprise_linux 8","enterprise_linux 9"],"cvss":8.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cvssSource":"vendor","cwe":["CWE-653"],"epss":0.00349,"epssPercentile":0.284,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-19T11:51:05.678002Z"},"scores":{"vendor":6.1,"adp":9.6},"slug":"CVE-2026-109740","body":"## Overview\n\nSandbox 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, … · updated 2026-10-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-109740.json)","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":220107,"id":"CVE-2026-109740","ts":1791978549651,"field":"cvss","old":null,"new":"8.8"},{"seq":220106,"id":"CVE-2026-109740","ts":1791978549651,"field":"severity","old":"none","new":"high"}]}