High8.6Cisco

High [CVE-2026-20012] Cisco IOS, IOS XE, Secure Firewall Adaptive Security Appliance, and Secure Firewall Threat Defense Software IKEv2 Denial of Service Vulnerability

This high-severity Cisco advisory covers CVE-2026-20012 affecting Cisco IOS 15.2(1)S1, Cisco IOS 15.2(4)S, Cisco IOS 15.2(1)S2.

cisco-sa-asa-ftd-ios-dos-kPEpQGGK Published Mar 25, 2026Updated by vendor Mar 25, 2026

CVE-2026-20012

Affected products & platforms

CiscoFirewallASA / FirepowerIOS XE

Open vendor advisory

Android app · Google Play

Monitor future Cisco CVEs from your phone.

Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.

Matching phone alertsOptional email delivery

Get CVE alerts See app features

Summary

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 …

Affected products named by the advisory: Cisco IOS 15.2(1)S1; Cisco IOS 15.2(4)S; Cisco IOS 15.2(1)S2; Cisco IOS 15.2(2)S1; and 2 more.

Affected versions

Scope: This vulnerability affects the following Cisco products if they have the IKEv2 VPN feature, including G-IKEv2, enabled:

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Mitigation checklist

Workaround status

There are no workarounds that address this vulnerability.

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Sources

Official and corroborating records used to build this advisory.

Cisco Security Advisories (PSIRT)official
Official vendor feed — the source of truth for this advisory. VulniPulse polled this feed and parsed this entry from it. Discovered from the machine-readable feed https://sec.cloudapps.cisco.com/security/center/psirtrss20/CiscoSecurityAdvisory.xml; this link opens the Cisco advisory index instead of the raw feed document.
Cisco
Vendor advisory pageofficial
Advisory page fetched and parsed to extract affected/fixed versions and mitigation guidance beyond what the feed carries.
Cisco

Cross-references

Validate CVE metadata against the authoritative registries.

CVE-2026-20012NVD CVE.org MITRE

Official resources

Cisco ASA upgrade guide
Official documentation
Official upgrade documentation for Cisco ASA (Adaptive Security Appliance) software.
Cisco Secure Firewall Threat Defense (FTD) upgrade guide
Official documentation
Official upgrade documentation for Cisco Secure Firewall Threat Defense (FTD) and FMC.
Cisco Secure Firewall compatibility & release notes
Release notes
Confirm FTD/FMC version compatibility before upgrading.
Cisco Software Checker
Official documentation
Official tool to confirm whether your exact IOS / IOS XE / NX-OS / ASA / FTD / SD-WAN release is affected and to find the first fixed release.

Discussion(0)

No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.