CVE-2026-20249

High

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.

SeverityHigh
CVSS8.6
Exploit probability—
ProductCisco Secure Firewall Adaptive Security Appliance (ASA) Software
PublishedSep 16, 2026
First seenSep 16, 2026
Weakness typeCWE-704CWE-704

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software9.16.1, 9.16.1.28, 9.16.2, 9.16.2.3, 9.16.2.7, 9.16.2.11, 9.16.2.13, 9.16.2.14, 9.16.3.3, 9.16.3, 9.16.3.14, 9.18.1, 9.16.3.15, 9.18.1.3, 9.18.2, 9.16.3.19, 9.16.3.23, 9.18.2.5, 9.16.4, 9.18.2.7, 9.19.1, 9.16.4.9, 9.18.2.8, 9.16.4.14, 9.18.3, 9.19.1.5, 9.16.4.18, 9.19.1.9, 9.18.3.39, 9.16.4.19, 9.19.1.12, 9.18.3.46, 9.16.4.27, 9.19.1.18, 9.18.3.53, 9.18.3.55, 9.16.4.38, 9.16.4.39, 9.18.3.56, 9.20.1, 9.16.4.42, 9.19.1.22, 9.18.4, 9.20.1.5, 9.18.4.5, 9.19.1.24, 9.16.4.48, 9.18.4.8, 9.20.2, 9.19.1.27, 9.16.4.55, 9.18.4.22, 9.20.2.10, 9.16.4.57, 9.19.1.28, 9.18.4.24, 9.20.2.21, 9.16.4.61, 9.19.1.31, 9.18.4.29, 9.20.2.22, 9.16.4.62, 9.18.4.34, 9.20.3, 9.16.4.67, 9.16.4.70, 9.18.4.40, 9.23.1, 9.22.1.1, 9.16.4.71, 9.20.3.4, 9.18.4.47, 9.20.3.7, 9.19.1.37, 9.16.4.76, 9.20.3.9, 9.19.1.38, 9.18.4.50, 9.22.1.3, 9.20.3.10, 9.22.1.2, 9.18.4.52, 9.20.3.13, 9.22.1.6, 9.18.4.53, 9.16.4.82, 9.22.2, 9.20.3.16, 9.19.1.42, 9.18.4.57, 9.16.4.84, 9.23.1.3, 9.20.3.20, 9.22.2.4, 9.23.1.7, 9.20.4, 9.22.2.9, 9.23.1.13, 9.20.4.7, 9.22.2.13, 9.18.4.66, 9.20.4.10, 9.23.1.19, 9.16.4.85, 9.22.2.14, 9.18.4.67, 9.24.1, 9.18.4.68, 9.23.1.22, 9.20.4.14, 9.22.2.20, 9.18.4.71, 9.20.4.19, 9.23.1.26, 9.16.4.89, 9.22.2.32, 9.18.4.76, 9.22.3, 9.24.1.5, 9.20.4.22, 9.24.1.9, 9.20.4.28, 9.16.4.92, 9.18.4.135, 9.23.1.195, 9.20.4.30, 9.24.1.155, 9.23.1.32, 9.18.4.82—
Cisco Cisco Secure Firewall Threat Defense (FTD) Software7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2, 7.2.0, 7.0.2.1, 7.0.3, 7.2.0.1, 7.0.4, 7.2.1, 7.0.5, 7.3.0, 7.2.2, 7.2.3, 7.3.1, 7.2.4, 7.0.6, 7.2.5, 7.2.4.1, 7.3.1.1, 7.4.0, 7.0.6.1, 7.2.5.1, 7.4.1, 7.2.6, 7.0.6.2, 7.4.1.1, 7.2.7, 7.2.5.2, 7.3.1.2, 7.2.8, 7.6.0, 7.4.2, 7.2.8.1, 7.0.6.3, 7.4.2.1, 7.2.9, 7.0.7, 7.7.0, 7.4.2.2, 7.2.10, 7.6.1, 7.4.2.3, 7.0.8, 7.6.2, 7.7.10, 7.7.11, 7.0.8.1, 7.6.2.1, 7.7.10.1, 7.4.2.4, 7.2.10.2, 7.4.3, 7.6.4, 10.0.0, 7.4.4, 7.0.9, 7.2.11, 7.4.7—

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