CVE-2021-38492
Estado: ModificadaMedia (6.5)—
When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92, Thunderbird < 91.1, Thunderbird < 78.14, Firefox ESR < 78.14, and Firefox ESR < 91.1.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- Puntuación base: 6.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 1.16%
- Percentil entre todas las CVEs puntuadas: 66
- Fecha de la puntuación: 7/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (3)
CWE
- NVD-CWE-noinfo
Referencias
- https://bugzilla.mozilla.org/show_bug.cgi?id=1721107
- https://security.gentoo.org/glsa/202208-14
- https://www.mozilla.org/security/advisories/mfsa2021-38/
- https://www.mozilla.org/security/advisories/mfsa2021-39/
- https://www.mozilla.org/security/advisories/mfsa2021-40/
- https://www.mozilla.org/security/advisories/mfsa2021-41/
- https://www.mozilla.org/security/advisories/mfsa2021-42/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1721107
- https://security.gentoo.org/glsa/202208-14
- https://www.mozilla.org/security/advisories/mfsa2021-38/
- https://www.mozilla.org/security/advisories/mfsa2021-39/
- https://www.mozilla.org/security/advisories/mfsa2021-40/
- https://www.mozilla.org/security/advisories/mfsa2021-41/
- https://www.mozilla.org/security/advisories/mfsa2021-42/
JSON original (NVD)
Mostrar
{
"id": "CVE-2021-38492",
"cveTags": [],
"metrics": {
"cvssMetricV2": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"version": "2.0",
"baseScore": 4.3,
"accessVector": "NETWORK",
"vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N",
"authentication": "NONE",
"integrityImpact": "PARTIAL",
"accessComplexity": "MEDIUM",
"availabilityImpact": "NONE",
"confidentialityImpact": "NONE"
},
"acInsufInfo": false,
"impactScore": 2.9,
"baseSeverity": "MEDIUM",
"obtainAllPrivilege": false,
"exploitabilityScore": 8.6,
"obtainUserPrivilege": false,
"obtainOtherPrivilege": false,
"userInteractionRequired": true
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 6.5,
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "REQUIRED",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 2.8
}
]
},
"affected": [
{
"source": "security@mozilla.org",
"affectedData": [
{
"vendor": "Mozilla",
"product": "Firefox",
"versions": [
{
"status": "affected",
"version": "unspecified",
"lessThan": "92",
"versionType": "custom"
}
]
},
{
"vendor": "Mozilla",
"product": "Thunderbird",
"versions": [
{
"status": "affected",
"version": "unspecified",
"lessThan": "91.1",
"versionType": "custom"
},
{
"status": "affected",
"version": "unspecified",
"lessThan": "78.14",
"versionType": "custom"
}
]
},
{
"vendor": "Mozilla",
"product": "Firefox ESR",
"versions": [
{
"status": "affected",
"version": "unspecified",
"lessThan": "78.14",
"versionType": "custom"
},
{
"status": "affected",
"version": "unspecified",
"lessThan": "91.1",
"versionType": "custom"
}
]
}
]
}
],
"published": "2021-11-03T01:15:07.200",
"references": [
{
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1721107",
"tags": [
"Exploit",
"Issue Tracking",
"Vendor Advisory"
],
"source": "security@mozilla.org"
},
{
"url": "https://security.gentoo.org/glsa/202208-14",
"tags": [
"Third Party Advisory"
],
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-38/",
"tags": [
"Vendor Advisory"
],
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-39/",
"tags": [
"Vendor Advisory"
],
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-40/",
"tags": [
"Vendor Advisory"
],
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-41/",
"tags": [
"Vendor Advisory"
],
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-42/",
"tags": [
"Vendor Advisory"
],
"source": "security@mozilla.org"
},
{
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1721107",
"tags": [
"Exploit",
"Issue Tracking",
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://security.gentoo.org/glsa/202208-14",
"tags": [
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-38/",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-39/",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-40/",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-41/",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2021-42/",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"description": [
{
"lang": "en",
"value": "NVD-CWE-noinfo"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92, Thunderbird < 91.1, Thunderbird < 78.14, Firefox ESR < 78.14, and Firefox ESR < 91.1."
},
{
"lang": "es",
"value": "Cuando se delegaba la navegación al sistema operativo, Firefox aceptaba el esquema \"mk\" que podía permitir a atacantes lanzar páginas y ejecutar scripts en Internet Explorer en modo no privilegiado. *Este bug sólo afecta a Firefox para Windows. Los demás sistemas operativos no están afectados*. Esta vulnerabilidad afecta a Firefox versiones anteriores a 92, Thunderbird versiones anteriores a 91.1, Thunderbird versiones anteriores a 78.14, Firefox ESR versiones anteriores a 78.14 y Firefox ESR versiones anteriores a 91.1"
}
],
"lastModified": "2026-06-17T04:02:13.113",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "117CF1EF-253C-4D02-96C4-EA184FC46C3A",
"versionEndExcluding": "92.0"
},
{
"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "5CE2287C-BD2C-4124-84B5-2AE73F0B4A99",
"versionEndExcluding": "91.1",
"versionStartIncluding": "91.0"
},
{
"criteria": "cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "CF306B4F-A578-4935-82BC-190F160F00CD",
"versionEndExcluding": "78.14"
},
{
"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "78AEE0F9-48F7-4838-9F35-286964487A5C",
"versionEndExcluding": "78.14"
},
{
"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "808DBD53-8A8F-4695-951C-DAF9AA17462E",
"versionEndExcluding": "91.1",
"versionStartIncluding": "91.0"
}
],
"operator": "OR"
},
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*",
"vulnerable": false,
"matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA"
}
],
"operator": "OR"
}
],
"operator": "AND"
}
],
"sourceIdentifier": "security@mozilla.org"
}