CVE-2026-20154

Name of the Vulnerable Software and Affected Versions Cisco Secure Firewall Adaptive Security Appliance (ASA) Software (affected versions not specified) Cisco Secure Firewall Threat Defense (FTD) Software (affected versions not specified)

Description An issue in the system rate-limiting process for syslog message 419002 allows an unauthenticated remote attacker to cause high CPU utilization, leading to a denial of service (DoS) condition. This occurs because of improper rate limiting for the specific syslog message. An attacker can trigger this by sending a flood of TCP synchronization (SYN) packets to the device, which results in performance degradation.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.