Vulnerability · Published Sep 16, 2026 · Assigned by cisco
CVE-2026-20249Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software IKEv2 Certificate Authentication Denial of Service Vulnerability
High 8.6
In plain English
A high-severity security flaw in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software | 9.16.19.16.1.289.16.29.16.2.39.16.2.79.16.2.119.16.2.139.16.2.14 |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.0.07.0.0.17.0.17.0.1.17.0.27.2.07.0.2.17.0.3 |
Weakness: CWE-704 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H