CVE-2025-20136
This vulnerability is due to an infinite loop condition that occurs when a Cisco Secure ASA or Cisco Secure FTD device processes DNS packets with DNS inspection enabled and the device is configured for NAT44, NAT64, or NAT46. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static NAT rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to create an infinite loop and cause the device to reload, resulting in a DoS condition.
Detalles técnicos trazas, registros y código del informe original
A vulnerability in the function that performs IPv4 and IPv6 Network Address Translation (NAT) DNS inspection for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.
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: 0.64%
- Percentil entre todas las CVEs puntuadas: 49
- 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 indica explotación remota sin privilegios (T1190). El ataque envía paquetes DNS craftados que causan bucle infinito y recarga del dispositivo, típico de DoS por agotamiento de recursos (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 (2)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-835
Referencias
JSON original (NVD)
Mostrar
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"version": "7.0.1"
},
{
"status": "affected",
"version": "7.1.0"
},
{
"status": "affected",
"version": "6.4.0.13"
},
{
"status": "affected",
"version": "6.6.5.1"
},
{
"status": "affected",
"version": "6.2.3.18"
},
{
"status": "affected",
"version": "7.0.1.1"
},
{
"status": "affected",
"version": "6.4.0.14"
},
{
"status": "affected",
"version": "7.1.0.1"
},
{
"status": "affected",
"version": "6.6.5.2"
},
{
"status": "affected",
"version": "7.0.2"
},
{
"status": "affected",
"version": "6.4.0.15"
},
{
"status": "affected",
"version": "7.2.0"
},
{
"status": "affected",
"version": "7.0.2.1"
},
{
"status": "affected",
"version": "7.0.3"
},
{
"status": "affected",
"version": "6.6.7"
},
{
"status": "affected",
"version": "7.1.0.2"
},
{
"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": "6.4.0.16"
},
{
"status": "affected",
"version": "7.3.0"
},
{
"status": "affected",
"version": "7.2.2"
},
{
"status": "affected",
"version": "7.2.3"
},
{
"status": "affected",
"version": "6.6.7.1"
},
{
"status": "affected",
"version": "7.3.1"
},
{
"status": "affected",
"version": "7.1.0.3"
},
{
"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": "6.4.0.17"
},
{
"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": "6.6.7.2"
},
{
"status": "affected",
"version": "6.4.0.18"
},
{
"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"
}
],
"defaultStatus": "unknown"
}
]
}
],
"published": "2025-08-14T17:15:35.063",
"references": [
{
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-nat-dns-dos-bqhynHTM",
"source": "psirt@cisco.com"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "psirt@cisco.com",
"description": [
{
"lang": "en",
"value": "CWE-835"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "A vulnerability in the function that performs IPv4 and IPv6 Network Address Translation (NAT) DNS inspection for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. \r\n\r\nThis vulnerability is due to an infinite loop condition that occurs when a Cisco Secure ASA or Cisco Secure FTD device processes DNS packets with DNS inspection enabled and the device is configured for NAT44, NAT64, or NAT46. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static NAT rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to create an infinite loop and cause the device to reload, resulting in a DoS condition."
},
{
"lang": "es",
"value": "Una vulnerabilidad en la función que realiza la inspección de DNS de la Traducción de Direcciones de Red (NAT) IPv4 e IPv6 para el software Cisco Secure Firewall Adaptive Security Appliance (ASA) y el software Cisco Secure Firewall Threat Defense (FTD) podría permitir que un atacante remoto no autenticado reinicie el dispositivo inesperadamente, lo que resulta en una denegación de servicio (DoS). Esta vulnerabilidad se debe a un bucle infinito que se produce cuando un dispositivo Cisco Secure ASA o Cisco Secure FTD procesa paquetes DNS con la inspección de DNS habilitada y está configurado para NAT44, NAT64 o NAT46. Un atacante podría explotar esta vulnerabilidad enviando paquetes DNS manipulados que coincidan con una regla NAT estática con la inspección de DNS habilitada a través de un dispositivo afectado. Una explotación exitosa podría permitir al atacante crear un bucle infinito y provocar la recarga del dispositivo, lo que resulta en una denegación de servicio (DoS)."
}
],
"lastModified": "2026-06-17T08:40:45.110",
"sourceIdentifier": "psirt@cisco.com"
}