--- id: CVE-2026-20154 title: >- 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, rem… summary: >- 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, rem… severity: high cvss: 8.6 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H' cwe: - CWE-835 vendor: Cisco product: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software affected: - secure_firewall_adaptive_security_appliance_asa_software 9.16.1 - secure_firewall_adaptive_security_appliance_asa_software 9.16.1.28 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.3 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.7 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.11 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.13 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.14 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.3 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.14 - secure_firewall_adaptive_security_appliance_asa_software 9.18.1 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.15 - secure_firewall_adaptive_security_appliance_asa_software 9.18.1.3 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.19 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.23 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2.5 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2.7 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.9 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2.8 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.14 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1.5 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.18 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1.9 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.39 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.19 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1.12 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.46 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.27 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1.18 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.53 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.55 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.38 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.39 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.56 - secure_firewall_adaptive_security_appliance_asa_software 9.20.1 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.42 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1.22 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4 - secure_firewall_adaptive_security_appliance_asa_software 9.20.1.5 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4.5 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1.24 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.48 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4.8 - secure_firewall_adaptive_security_appliance_asa_software 9.20.2 - secure_firewall_adaptive_security_appliance_asa_software 9.19.1.27 published: '2026-09-16' updated: '2026-09-18' sourceUpdated: '2026-09-18T15:17:06.753' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20154' references: - url: >- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-logging-dos-ZXXNesfN label: psirt@cisco.com - url: 'https://software.cisco.com' tags: - nvd - cve.org - csaf - vendor-advisory - cisco ssvc: exploitation: none automatable: 'yes' technicalImpact: partial timestamp: '2026-09-18T14:39:37.915604Z' epss: 0.00404 epssPercentile: 0.31798 ingestedAt: '2026-09-16T16:37:52.189Z' --- ## Overview 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.  ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **cisco-sa-asa-ftd-logging-dos-ZXXNesfN** · Cisco · affected: Cisco Firepower 2100 Series, Cisco Firepower 1000 Series, Cisco ASA 5500-X Series Firewalls, Cisco 3000 Series Industrial Security Appliances (ISA), Cisco Firepower 9000 Series, Cisco Firepower 4100 Series, … · updated 2026-09-18 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-logging-dos-ZXXNesfN)