{"id":"CVE-2020-3554","title":"A vulnerability in the TCP packet processing of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) conditi…","summary":"A vulnerability in the TCP packet processing of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) conditi…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-400","CWE-400"],"vendor":"cisco","product":"adaptive_security_appliance","affected":["adaptive_security_appliance < 9.12.4.3","secure_firewall_threat_defense <= 6.2.2","secure_firewall_threat_defense >= 6.3.0, < 6.4.0.10","secure_firewall_threat_defense >= 6.5.0, < 6.5.0.5","secure_firewall_threat_defense = 6.6.0","adaptive_security_appliance_software >= 9.13.0, < 9.13.1.13","adaptive_security_appliance_software >= 9.14.0, < 9.14.1.30"],"patched":["adaptive_security_appliance 9.12.4.3","secure_firewall_threat_defense 6.5.0.5","adaptive_security_appliance_software 9.14.1.30"],"published":"2020-10-21","updated":"2026-08-11","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-3554","references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-dos-QFcNEPfx","label":"psirt@cisco.com"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-dos-QFcNEPfx","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.02665,"epssPercentile":0.84998,"ingestedAt":"2026-08-11T19:48:28.776Z","slug":"CVE-2020-3554","body":"## Overview\n\nA vulnerability in the TCP packet processing of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory exhaustion condition. An attacker could exploit this vulnerability by sending a high rate of crafted TCP traffic through an affected device. A successful exploit could allow the attacker to exhaust device resources, resulting in a DoS condition for traffic transiting the affected device.\n\n## Affected\n\n- `adaptive_security_appliance < 9.12.4.3`\n- `secure_firewall_threat_defense <= 6.2.2`\n- `secure_firewall_threat_defense >= 6.3.0, < 6.4.0.10`\n- `secure_firewall_threat_defense >= 6.5.0, < 6.5.0.5`\n- `secure_firewall_threat_defense = 6.6.0`\n- `adaptive_security_appliance_software >= 9.13.0, < 9.13.1.13`\n- `adaptive_security_appliance_software >= 9.14.0, < 9.14.1.30`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `adaptive_security_appliance 9.12.4.3`\n- `secure_firewall_threat_defense 6.5.0.5`\n- `adaptive_security_appliance_software 9.14.1.30`","depth":"twilight","depthScore":42,"depthScoreParts":{"impact":41.3,"likelihood":0.5,"exploitation":0,"ransomware":0},"changes":[]}