CVE-2026-20222: Cisco Secure Firewall Adaptive Security Appliance ASA Software

High severity, CVSS 7.4. EPSS: 0.2% chance of exploitation in the next 30 days.

A vulnerability in the EIGRP implementation in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper resource management when handling EIGRP update messages. An attacker could exploit this vulnerability by sending crafted EIGRP updates at a high rate to an affected device. A successful exploit could allow the attacker to trigger a memory leak that will eventually cause the affected device to reload unexpectedly.

Affected products

• Cisco Cisco Secure Firewall Adaptive Security Appliance ASA Software: version 9.19.1 only; version 9.19.1.5 only; version 9.19.1.9 only; version 9.19.1.12 only; version 9.19.1.18 only; version 9.20.1 only; …
• Cisco Cisco Secure Firewall Threat Defense FTD Software: version 7.3.0 only; version 7.3.1 only; version 7.3.1.1 only; version 7.4.0 only; version 7.4.1 only; version 7.4.1.1 only; …

Published 2026-09-16. Last modified 2026-09-18.