CVE-2026-20249

HIGH

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 Fir...

Affects 0 products across 1 vendor.

CVSS 3.18.6
EPSS0.4%
Percentile32th
PatchUnknown
CVSS Vector — Plain English Remotely exploitable over the network, low complexity, no authentication required, no user interaction needed, can impact systems beyond the vulnerable component, no confidentiality impact, no integrity impact, full availability impact.
CWE Weakness Definitions
CWE-704: CWE-704
◆ AI Analysis — automated analysis, not human-reviewed

A high severity vulnerability (CVE-2026-20249) affects the target system. 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 un...

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Frequently Asked Questions
What is CVE-2026-20249?
A high severity vulnerability (CVE-2026-20249) affects the target system. 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 un...
What is the CVSS score for CVE-2026-20249?
CVE-2026-20249 has CVSS 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H. EPSS: 0.4%.
Is CVE-2026-20249 actively exploited?
No confirmed active exploitation of CVE-2026-20249 as of 2026-09-25.
How do I remediate CVE-2026-20249?
Apply vendor patches for CVE-2026-20249. Monitor Cisco advisories.
What systems are affected by CVE-2026-20249?
CVE-2026-20249 affects: Cisco.
Vulnerability Details
CVE IDCVE-2026-20249
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Published2026-09-16
Last Modified2026-09-18
ICS Relevance65%
Weakness (CWE)
CWE-704
SourceNVD
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.

Source: NIST NVD / MITRE CVE Database

Affected Products
VendorProductFixed Version
Cisco — —
Remediation

No patch URL on record. Monitor vendor security advisories directly.

Threat Intelligence
● Threat Intelligence Validated: September 2026 | Threat Age: 11 Days
CISA KEVNot in KEV catalog
Public ExploitNot confirmed
PoC CodeNot confirmed
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