CVE-2025-20134
A vulnerability in the certificate processing of 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.
This vulnerability is due to improper parsing of SSL/TLS certificates. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
CVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- Base score: 8.6
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 0.42%
- Percentile among all scored CVEs: 34
- Score date: 10/5/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
🎯 ATT&CK techniques
How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.
- Exploitation
T1190Exploit Public-Facing Applicationinitial access95 % - Primary impact
T1499.004Application or System Exploitationimpact90 %
Vulnerabilidad remota sin autenticación ni interacción (AV:N/PR:N/UI:N) explotada via paquetes DNS malformados contra servicio expuesto (T1190). El impacto es DoS por recarga no esperada del dispositivo (T1499.004: endpoint denial of service).
Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.
🛡️ ATT&CK mitigations that cover these techniques
Affected technologies (2)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
CWEs
- CWE-415
References
Raw JSON (NVD)
Show
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"published": "2025-08-14T17:15:34.637",
"references": [
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"source": "psirt@cisco.com"
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"value": "A vulnerability in the certificate processing of 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 improper parsing of SSL/TLS certificates. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition."
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"value": "Una vulnerabilidad en el procesamiento de certificados del software Cisco Secure Firewall Adaptive Security Appliance (ASA) y del 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 análisis incorrecto de certificados SSL/TLS. Un atacante podría explotar esta vulnerabilidad enviando un certificado SSL/TLS manipulado a un sistema afectado a través de un socket SSL/TLS en espera. Una explotación exitosa podría permitir que el atacante reinicie el dispositivo, lo que resulta en una denegación de servicio (DoS)."
}
],
"lastModified": "2026-06-17T08:40:44.777",
"sourceIdentifier": "psirt@cisco.com"
}