CVE-2026-20135
A vulnerability in the TLS 1.3 implementation in Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition.
This vulnerability is due to improper buffer management during the TLS 1.3 connection. An attacker could exploit this vulnerability by sending a crafted TLS 1.3 packet to an affected system through a TLS 1.3-enabled listening socket. A successful exploit could allow the attacker to cause the LINA process to crash, which would cause the device to reload. The reload can happen before or after authentication of the connection.Note: TLS 1.3 connections include both data traffic and user-management traffic.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- Puntuación base: 8.6
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.46%
- Percentil entre todas las CVEs puntuadas: 38
- Fecha de la puntuación: 6/10/2026
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
T1190Exploit Public-Facing Applicationinitial access95 % - Impacto principal
T1499.004Application or System Exploitationimpact90 %
Vector AV:N/AC:L/PR:N/UI:N indica explotación remota sin autenticación previa (T1190). CWE-415 (buffer management) causa crash del proceso LINA y recarga del dispositivo, tipificando DoS de servicio de aplicación (T1499.004).
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-415
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-20135",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-20135",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-09-17T13:35:03.490455Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "psirt@cisco.com",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 8.6,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 4,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "psirt@cisco.com",
"affectedData": [
{
"vendor": "Cisco",
"product": "Cisco Secure Firewall Threat Defense (FTD) Software",
"versions": [
{
"status": "affected",
"version": "7.0.0"
},
{
"status": "affected",
"version": "7.0.0.1"
},
{
"status": "affected",
"version": "7.0.1"
},
{
"status": "affected",
"version": "7.0.1.1"
},
{
"status": "affected",
"version": "7.0.2"
},
{
"status": "affected",
"version": "7.2.0"
},
{
"status": "affected",
"version": "7.0.2.1"
},
{
"status": "affected",
"version": "7.0.3"
},
{
"status": "affected",
"version": "7.2.0.1"
},
{
"status": "affected",
"version": "7.0.4"
},
{
"status": "affected",
"version": "7.2.1"
},
{
"status": "affected",
"version": "7.0.5"
},
{
"status": "affected",
"version": "7.3.0"
},
{
"status": "affected",
"version": "7.2.2"
},
{
"status": "affected",
"version": "7.2.3"
},
{
"status": "affected",
"version": "7.3.1"
},
{
"status": "affected",
"version": "7.2.4"
},
{
"status": "affected",
"version": "7.0.6"
},
{
"status": "affected",
"version": "7.2.5"
},
{
"status": "affected",
"version": "7.2.4.1"
},
{
"status": "affected",
"version": "7.3.1.1"
},
{
"status": "affected",
"version": "7.4.0"
},
{
"status": "affected",
"version": "7.0.6.1"
},
{
"status": "affected",
"version": "7.2.5.1"
},
{
"status": "affected",
"version": "7.4.1"
},
{
"status": "affected",
"version": "7.2.6"
},
{
"status": "affected",
"version": "7.0.6.2"
},
{
"status": "affected",
"version": "7.4.1.1"
},
{
"status": "affected",
"version": "7.2.7"
},
{
"status": "affected",
"version": "7.2.5.2"
},
{
"status": "affected",
"version": "7.3.1.2"
},
{
"status": "affected",
"version": "7.2.8"
},
{
"status": "affected",
"version": "7.6.0"
},
{
"status": "affected",
"version": "7.4.2"
},
{
"status": "affected",
"version": "7.2.8.1"
},
{
"status": "affected",
"version": "7.0.6.3"
},
{
"status": "affected",
"version": "7.4.2.1"
},
{
"status": "affected",
"version": "7.2.9"
},
{
"status": "affected",
"version": "7.0.7"
},
{
"status": "affected",
"version": "7.7.0"
},
{
"status": "affected",
"version": "7.4.2.2"
},
{
"status": "affected",
"version": "7.2.10"
},
{
"status": "affected",
"version": "7.6.1"
},
{
"status": "affected",
"version": "7.4.2.3"
},
{
"status": "affected",
"version": "7.0.8"
},
{
"status": "affected",
"version": "7.6.2"
},
{
"status": "affected",
"version": "7.7.10"
},
{
"status": "affected",
"version": "7.7.11"
},
{
"status": "affected",
"version": "7.0.8.1"
},
{
"status": "affected",
"version": "7.6.2.1"
},
{
"status": "affected",
"version": "7.7.10.1"
},
{
"status": "affected",
"version": "7.4.2.4"
},
{
"status": "affected",
"version": "7.2.10.2"
},
{
"status": "affected",
"version": "7.4.3"
},
{
"status": "affected",
"version": "7.6.4"
},
{
"status": "affected",
"version": "7.4.4"
},
{
"status": "affected",
"version": "7.0.9"
},
{
"status": "affected",
"version": "7.2.11"
}
],
"defaultStatus": "unknown"
}
]
}
],
"published": "2026-09-16T21:17:07.587",
"references": [
{
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls1.3-dos-dLxwFWgF",
"source": "psirt@cisco.com"
}
],
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"type": "Secondary",
"source": "psirt@cisco.com",
"description": [
{
"lang": "en",
"value": "CWE-415"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "A vulnerability in the TLS 1.3 implementation in Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to improper buffer management during the TLS 1.3 connection. An attacker could exploit this vulnerability by sending a crafted TLS 1.3 packet to an affected system through a TLS 1.3-enabled listening socket. A successful exploit could allow the attacker to cause the LINA process to crash, which would cause the device to reload. The reload can happen before or after authentication of the connection.Note: TLS 1.3 connections include both data traffic and user-management traffic."
}
],
"lastModified": "2026-09-18T13:28:28.567",
"sourceIdentifier": "psirt@cisco.com"
}