Vulnerability in Cisco Secure Firewall Adaptive Security Appliance (Asa) Software
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (36.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000
Affected products
- Cisco Secure Firewall Adaptive Security Appliance (Asa) Software — versions 9.16.1, 9.16.1.28, 9.16.2
- Cisco Secure Firewall Threat Defense (Ftd) Software — versions 10.0.0, 7.0.0, 7.0.0.1
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-20249?
- CVE-2026-20249 is a high-severity vulnerability in Cisco Secure Firewall Adaptive Security Appliance (Asa) Software, classified under Incorrect Type Conversion or Cast. CVSS score: 8.6/10. Published 2026-09-16.
- How severe is CVE-2026-20249?
- High severity. CVSS v3 base score is 8.6 out of 10.