CVE-2026-20249

A vulnerability in the certification authentication feature of Internet Key Exchange version 2 (IKEv2) 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 an affected device to reload unexpectedly. This vulnerability is due to a logic error during the certificate authentication phase of the IKEv2 connection setup. An attacker could exploit this vulnerability by attempting to establish an IKEv2 VPN connection with a crafted certificate. A successful exploit could allow the attacker to cause the IKEv2 process to crash, causing a denial of service (DoS) condition.

CVSS v3 8.6 HIGH

8.6^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 4.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ikev2cert-dos-uWyc2xtv

Configurations

No configuration.

History

16 Sep 2026, 21:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-16 21:17

Updated : 2026-09-18 15:17

NVD link : CVE-2026-20249

Mitre link : CVE-2026-20249

CVE.ORG link : CVE-2026-20249

JSON object : View

Products Affected

No product.

CWE

CWE-704

Incorrect Type Conversion or Cast

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"unknown"}]}], "published": "2026-09-16T21:17:08.517", "references": [{"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ikev2cert-dos-uWyc2xtv", "source": "psirt@cisco.com"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "psirt@cisco.com", "description": [{"lang": "en", "value": "CWE-704"}]}], "descriptions": [{"lang": "en", "value": "A vulnerability in the certification authentication feature of Internet Key Exchange version 2 (IKEv2) 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 an affected device to reload unexpectedly.\r\n\r\nThis vulnerability is due to a logic error during the certificate authentication phase of the IKEv2 connection setup. An attacker could exploit this vulnerability by attempting to establish an IKEv2 VPN connection with a crafted certificate. A successful exploit could allow the attacker to cause the IKEv2 process to crash, causing a denial of service (DoS) condition."}], "lastModified": "2026-09-18T15:17:06.947", "sourceIdentifier": "psirt@cisco.com"}