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Vulnerabilities

Vulnerability · CVE-2026-20012

A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance…

Published Mar 25, 2026 · catalog updated Sep 17, 2026 · secure firewall threat defense

Check if you run it

No confirmed exploitation is on record for CVE-2026-20012. EPSS is 0.35%. Act only if a listed version of secure firewall threat defense is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.35%
Remediation
Advisory link
Affected products
cpe cisco/secure firewall threat defense

A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition on an affected device. This vulnerability is due to improper parsing of IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. A successful exploit of Cisco IOS Software and IOS XE Software could allow the attacker to cause the affected device to reload, resulting in a DoS condition. A successful exploit of Cisco Secure Firewall ASA Software and Secure FTD Software could allow the attacker to partially exhaust system memory, resulting in system instability, such as the inability to establish new IKEv2 VPN sessions. A manual reboot of the device is required to recover from this condition.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe cisco/secure firewall threat defense6.2.3
  • cpe cisco/secure firewall threat defense6.2.3.1
  • cpe cisco/secure firewall threat defense6.2.3.2
  • cpe cisco/secure firewall threat defense6.2.3.3
  • cpe cisco/secure firewall threat defense6.2.3.4
  • cpe cisco/secure firewall threat defense6.2.3.5
  • cpe cisco/secure firewall threat defense6.2.3.6
  • cpe cisco/secure firewall threat defense6.2.3.7

How to fix CVE-2026-20012

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-20012. EPSS is 0.35%. Act only if a listed version of secure firewall threat defense is installed.

Which versions are affected?

Compare what you have installed with cisco/secure firewall threat defense 6.2.3; cisco/secure firewall threat defense 6.2.3.1; cisco/secure firewall threat defense 6.2.3.2; cisco/secure firewall threat defense 6.2.3.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-401: Missing Release of Memory after Effective Lifetime. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 25, 2026 · NIST NVD

    Detected

    A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition on an affected device. This vulnerabil

  2. Sep 17, 2026 · NIST NVD

    Updated

    A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition on an affected device. This vulnerabil

Sources

  • CVE.orgVulnerability recordCVE-2026-20012

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-20012

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-20012

    A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote at

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.