CVE-2026-100766
Information disclosure in the Networking: JAR component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
- Puntuación base: 4.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.27%
- Percentil entre todas las CVEs puntuadas: 17
- Fecha de la puntuación: 4/10/2026
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).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1203Exploitation for Client Executionexecution75 % - Impacto principal
T1005Data from Local Systemcollection80 %
Vector AV:N/UI:R indica explotación remota con interacción del usuario (T1203). CWE-200 (información disclosure) en componente JAR de navegador confirma lectura de datos (T1005) como impacto principal.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-200
Referencias
- https://bugzilla.mozilla.org/show_bug.cgi?id=2061526
- https://www.mozilla.org/security/advisories/mfsa2026-100/
- https://www.mozilla.org/security/advisories/mfsa2026-101/
- https://www.mozilla.org/security/advisories/mfsa2026-102/
- https://www.mozilla.org/security/advisories/mfsa2026-103/
- https://www.mozilla.org/security/advisories/mfsa2026-97/
- https://www.mozilla.org/security/advisories/mfsa2026-98/
- https://www.mozilla.org/security/advisories/mfsa2026-99/
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-100766",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-100766",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-09-29T15:09:26.697827Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 4.3,
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N",
"integrityImpact": "NONE",
"userInteraction": "REQUIRED",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "LOW"
},
"impactScore": 1.4,
"exploitabilityScore": 2.8
}
]
},
"affected": [
{
"source": "security@mozilla.org",
"affectedData": [
{
"vendor": "Mozilla",
"product": "Firefox",
"versions": [
{
"status": "unaffected",
"version": "115.42",
"versionType": "rpm",
"lessThanOrEqual": "115.*"
},
{
"status": "unaffected",
"version": "140.17",
"versionType": "rpm",
"lessThanOrEqual": "140.*"
},
{
"status": "unaffected",
"version": "153.4",
"versionType": "rpm",
"lessThanOrEqual": "153.*"
},
{
"status": "unaffected",
"version": "157",
"versionType": "rpm",
"lessThanOrEqual": "*"
}
]
},
{
"vendor": "Mozilla",
"product": "Thunderbird",
"versions": [
{
"status": "unaffected",
"version": "140.17",
"versionType": "rpm",
"lessThanOrEqual": "140.*"
},
{
"status": "unaffected",
"version": "153.4",
"versionType": "rpm",
"lessThanOrEqual": "153.*"
},
{
"status": "unaffected",
"version": "157",
"versionType": "rpm",
"lessThanOrEqual": "*"
}
]
}
]
}
],
"published": "2026-09-29T13:17:40.837",
"references": [
{
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2061526",
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-100/",
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-101/",
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-102/",
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-103/",
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-97/",
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-98/",
"source": "security@mozilla.org"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-99/",
"source": "security@mozilla.org"
}
],
"vulnStatus": "Undergoing Analysis",
"weaknesses": [
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"description": [
{
"lang": "en",
"value": "CWE-200"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Information disclosure in the Networking: JAR component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17."
}
],
"lastModified": "2026-09-30T18:18:04.057",
"sourceIdentifier": "security@mozilla.org"
}