CVE-2026-20154: Cisco Secure Firewall Adaptive Security Appliance Software and Secure Firewall Threat Defense Software Logging Denial of Service
A vulnerability in the system rate-limiting process for syslog message 419002 of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause high CPU utilization on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improper rate limiting for syslog message 419002. An attacker could exploit this vulnerability by sending a flood of TCP synchronization (SYN) packets to an affected device. A successful exploit could allow the attacker to cause high CPU utilization, resulting in performance degradation.
Affected Software
Event History
Frequently Asked Questions
What does an attacker need to do to trigger the issue?
An unauthenticated remote attacker can exploit the issue by sending a flood of TCP SYN packets to an affected device. No privileges or user interaction are required.
What is the operational impact of successful exploitation?
Exploitation can drive high CPU utilization on the affected device, causing performance degradation and potentially a denial-of-service condition. The described impact is availability-related; no confidentiality or integrity impact is stated.
Which systems are in scope?
The issue affects Cisco Secure Firewall ASA Software and Cisco Secure Firewall FTD Software. The provided information does not identify affected or fixed software versions.