CVE-2026-20249
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software IKEv2 Certificate Authentication Denial of Service Vulnerability
- Published
- Updated
- Reserved
- Assigned by
- cisco
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| ciscoCNA (assigner) | 3.1 | High8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVDNVD · Awaiting Analysis | 3.1 | High8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.42% · top 64% of all CVEs (5 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.
Weakness
Affected products
Cisco · Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
- affected 9.16.1
- affected 9.16.1.28
- affected 9.16.2
- affected 9.16.2.3
- affected 9.16.2.7
- affected 9.16.2.11
- affected 9.16.2.13
- affected 9.16.2.14
- affected 9.16.3.3
- affected 9.16.3
- affected 9.16.3.14
- affected 9.18.1
- affected 9.16.3.15
- affected 9.18.1.3
- affected 9.18.2
- affected 9.16.3.19
- affected 9.16.3.23
- affected 9.18.2.5
- affected 9.16.4
- affected 9.18.2.7
- affected 9.19.1
- affected 9.16.4.9
- affected 9.18.2.8
- affected 9.16.4.14
- affected 9.18.3
- affected 9.19.1.5
- affected 9.16.4.18
- affected 9.19.1.9
- affected 9.18.3.39
- affected 9.16.4.19
- affected 9.19.1.12
- affected 9.18.3.46
- affected 9.16.4.27
- affected 9.19.1.18
- affected 9.18.3.53
- affected 9.18.3.55
- affected 9.16.4.38
- affected 9.16.4.39
- affected 9.18.3.56
- affected 9.20.1
- and 89 more
Cisco · Cisco Secure Firewall Threat Defense (FTD) Software
- affected 7.0.0
- affected 7.0.0.1
- affected 7.0.1
- affected 7.0.1.1
- affected 7.0.2
- affected 7.2.0
- affected 7.0.2.1
- affected 7.0.3
- affected 7.2.0.1
- affected 7.0.4
- affected 7.2.1
- affected 7.0.5
- affected 7.3.0
- affected 7.2.2
- affected 7.2.3
- affected 7.3.1
- affected 7.2.4
- affected 7.0.6
- affected 7.2.5
- affected 7.2.4.1
- affected 7.3.1.1
- affected 7.4.0
- affected 7.0.6.1
- affected 7.2.5.1
- affected 7.4.1
- affected 7.2.6
- affected 7.0.6.2
- affected 7.4.1.1
- affected 7.2.7
- affected 7.2.5.2
- affected 7.3.1.2
- affected 7.2.8
- affected 7.6.0
- affected 7.4.2
- affected 7.2.8.1
- affected 7.0.6.3
- affected 7.4.2.1
- affected 7.2.9
- affected 7.0.7
- affected 7.7.0
- and 20 more
What to do
Exploitation: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
References (1)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-20249)Record last updated .