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CVE-2026-20249

8.6 HIGHEPSS 0.40%
  1. Published16 Sept 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeChanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2026-20249 being actively exploited?

CVE-2026-20249 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.40%.

How severe is CVE-2026-20249?

CVE-2026-20249 has a CVSS 3.1 base score of 8.6, rated high. EPSS estimates a 0.40% probability of exploitation.

How do I fix CVE-2026-20249?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-20249 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.