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CVE-2026-20249

HIGHCVSS 8.6/10

Last modified

CVE-2026-20249 is a high-severity vulnerability rated 8.6/10 on the CVSS scale. 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.

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.

Metrics

CVSS 3.1
8.6/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
CiscoCisco 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
CiscoCisco 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

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is 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.
How severe is CVE-2026-20249?
CVE-2026-20249 has a CVSS score of 8.6/10 (HIGH severity).
How do I fix CVE-2026-20249?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST