CVE-2026-109740
Full vulnerability record from the local CVENow database.
Description
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
CRITICAL
CVSS score
9.6
(v3.1)
Vulnerability status
Deferred
Source identifier
Published
2026-10-13 13:17:24.587000
Last modified
2026-10-19 12:16:59.840000
View original CVE JSON
{
"id": "CVE-2026-109740",
"sourceIdentifier": "[email protected]",
"published": "2026-10-13T13:17:24.587",
"lastModified": "2026-10-19T12:16:59.840",
"vulnStatus": "Deferred",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "Mozilla",
"product": "Firefox",
"versions": [
{
"version": "153.5",
"lessThanOrEqual": "153.*",
"versionType": "rpm",
"status": "unaffected"
},
{
"version": "158",
"lessThanOrEqual": "*",
"versionType": "rpm",
"status": "unaffected"
}
]
},
{
"vendor": "Mozilla",
"product": "Thunderbird",
"versions": [
{
"version": "153.5",
"lessThanOrEqual": "153.*",
"versionType": "rpm",
"status": "unaffected"
},
{
"version": "158",
"lessThanOrEqual": "*",
"versionType": "rpm",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
"baseScore": 9.6,
"baseSeverity": "CRITICAL",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "REQUIRED",
"scope": "CHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 2.8,
"impactScore": 6.0
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-19T11:51:05.678002Z",
"id": "CVE-2026-109740",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-119"
}
]
}
],
"references": [
{
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2057113",
"source": "[email protected]"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-106/",
"source": "[email protected]"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-108/",
"source": "[email protected]"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-109/",
"source": "[email protected]"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-110/",
"source": "[email protected]"
}
]
}