Cisco ASA/FTD EIGRP DoS via Unauthenticated Adjacent Attacker
CVE-2026-20222 Published on September 16, 2026
Cisco Secure Adaptive Security Appliance Software and Secure Firewall Threat Defense Software EIGRP Denial of Service Vulnerability
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.
Vulnerability Analysis
Weakness Type
What is a Memory Leak Vulnerability?
The software does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is often triggered by improper handling of malformed data or unexpectedly interrupted sessions. In some languages, developers are responsible for tracking memory allocation and releasing the memory. If there are no more pointers or references to the memory, then it can no longer be tracked and identified for release.
CVE-2026-20222 has been classified to as a Memory Leak vulnerability or weakness.
Products Associated with CVE-2026-20222
Want to know whenever a new CVE is published for Cisco Adaptive Security Appliance? stack.watch will email you.
Affected Versions
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software:- Version 9.19.1 is affected.
- Version 9.19.1.5 is affected.
- Version 9.19.1.9 is affected.
- Version 9.19.1.12 is affected.
- Version 9.19.1.18 is affected.
- Version 9.20.1 is affected.
- Version 9.19.1.22 is affected.
- Version 9.20.1.5 is affected.
- Version 9.19.1.24 is affected.
- Version 9.20.2 is affected.
- Version 9.19.1.27 is affected.
- Version 9.20.2.10 is affected.
- Version 9.19.1.28 is affected.
- Version 9.20.2.21 is affected.
- Version 9.19.1.31 is affected.
- Version 9.20.2.22 is affected.
- Version 9.20.3 is affected.
- Version 9.23.1 is affected.
- Version 9.22.1.1 is affected.
- Version 9.20.3.4 is affected.
- Version 9.20.3.7 is affected.
- Version 9.19.1.37 is affected.
- Version 9.20.3.9 is affected.
- Version 9.19.1.38 is affected.
- Version 9.22.1.3 is affected.
- Version 9.20.3.10 is affected.
- Version 9.22.1.2 is affected.
- Version 9.20.3.13 is affected.
- Version 9.22.1.6 is affected.
- Version 9.22.2 is affected.
- Version 9.20.3.16 is affected.
- Version 9.19.1.42 is affected.
- Version 9.23.1.3 is affected.
- Version 9.20.3.20 is affected.
- Version 9.22.2.4 is affected.
- Version 9.23.1.7 is affected.
- Version 9.20.4 is affected.
- Version 9.22.2.9 is affected.
- Version 9.23.1.13 is affected.
- Version 9.20.4.7 is affected.
- Version 9.22.2.13 is affected.
- Version 9.20.4.10 is affected.
- Version 9.23.1.19 is affected.
- Version 9.22.2.14 is affected.
- Version 9.24.1 is affected.
- Version 9.23.1.22 is affected.
- Version 9.20.4.14 is affected.
- Version 9.22.2.20 is affected.
- Version 9.20.4.19 is affected.
- Version 9.23.1.26 is affected.
- Version 9.22.2.32 is affected.
- Version 9.22.3 is affected.
- Version 9.24.1.5 is affected.
- Version 9.20.4.22 is affected.
- Version 9.24.1.9 is affected.
- Version 9.20.4.28 is affected.
- Version 9.22.3.5 is affected.
- Version 9.23.1.195 is affected.
- Version 9.20.4.30 is affected.
- Version 9.24.1.155 is affected.
- Version 9.23.1.32 is affected.
- Version 9.24.1.11 is affected.
- Version 9.20.4.34 is affected.
- Version 9.20.4.235 is affected.
- Version 7.3.0 is affected.
- Version 7.3.1 is affected.
- Version 7.3.1.1 is affected.
- Version 7.4.0 is affected.
- Version 7.4.1 is affected.
- Version 7.4.1.1 is affected.
- Version 7.3.1.2 is affected.
- Version 7.6.0 is affected.
- Version 7.4.2 is affected.
- Version 7.4.2.1 is affected.
- Version 7.7.0 is affected.
- Version 7.4.2.2 is affected.
- Version 7.6.1 is affected.
- Version 7.4.2.3 is affected.
- Version 7.6.2 is affected.
- Version 7.7.10 is affected.
- Version 7.7.11 is affected.
- Version 7.6.2.1 is affected.
- Version 7.7.10.1 is affected.
- Version 7.4.2.4 is affected.
- Version 7.4.3 is affected.
- Version 7.6.4 is affected.
- Version 10.0.0 is affected.
- Version 7.4.4 is affected.
- Version 7.4.7 is affected.