{"id":"CVE-2020-3283","title":"A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Firepower Threat Defense (FTD) Software when running on the Cisco Firepower 1000 Series platform could allow an unauthenticated, remote att…","summary":"A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Firepower Threat Defense (FTD) Software when running on the Cisco Firepower 1000 Series platform could allow an unauthenticated, remote att…","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-119","CWE-787"],"vendor":"cisco","product":"secure_firewall_threat_defense","affected":["secure_firewall_threat_defense >= 6.4.0, < 6.4.0.9","asa_5505_firmware = 9.12(2.12)","asa_5505_firmware = 9.13(0.33)","asa_5510_firmware = 9.12(2.12)","asa_5510_firmware = 9.13(0.33)","asa_5512-x_firmware = 9.12(2.12)","asa_5512-x_firmware = 9.13(0.33)","asa_5515-x_firmware = 9.12(2.12)","asa_5515-x_firmware = 9.13(0.33)","asa_5520_firmware = 9.12(2.12)","asa_5520_firmware = 9.13(0.33)","asa_5525-x_firmware = 9.12(2.12)","asa_5525-x_firmware = 9.13(0.33)","asa_5540_firmware = 9.12(2.12)","asa_5540_firmware = 9.13(0.33)","asa_5545-x_firmware = 9.12(2.12)","asa_5545-x_firmware = 9.13(0.33)","asa_5550_firmware = 9.12(2.12)","asa_5550_firmware = 9.13(0.33)","asa_5555-x_firmware = 9.12(2.12)","asa_5555-x_firmware = 9.13(0.33)","asa_5580_firmware = 9.12(2.12)","asa_5580_firmware = 9.13(0.33)","asa_5585-x_firmware = 9.12(2.12)","asa_5585-x_firmware = 9.13(0.33)"],"patched":["secure_firewall_threat_defense 6.4.0.9"],"published":"2020-05-06","updated":"2026-08-11","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-3283","references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-dos-4v5nmWtZ","label":"psirt@cisco.com"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-dos-4v5nmWtZ","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.02005,"epssPercentile":0.79911,"ingestedAt":"2026-08-11T19:48:27.782Z","slug":"CVE-2020-3283","body":"## Overview\n\nA vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Firepower Threat Defense (FTD) Software when running on the Cisco Firepower 1000 Series platform could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device. The vulnerability is due to a communication error between internal functions. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause a buffer underrun, which leads to a crash. The crash causes the affected device to reload.\n\n## Affected\n\n- `secure_firewall_threat_defense >= 6.4.0, < 6.4.0.9`\n- `asa_5505_firmware = 9.12(2.12)`\n- `asa_5505_firmware = 9.13(0.33)`\n- `asa_5510_firmware = 9.12(2.12)`\n- `asa_5510_firmware = 9.13(0.33)`\n- `asa_5512-x_firmware = 9.12(2.12)`\n- `asa_5512-x_firmware = 9.13(0.33)`\n- `asa_5515-x_firmware = 9.12(2.12)`\n- `asa_5515-x_firmware = 9.13(0.33)`\n- `asa_5520_firmware = 9.12(2.12)`\n- `asa_5520_firmware = 9.13(0.33)`\n- `asa_5525-x_firmware = 9.12(2.12)`\n- `asa_5525-x_firmware = 9.13(0.33)`\n- `asa_5540_firmware = 9.12(2.12)`\n- `asa_5540_firmware = 9.13(0.33)`\n- `asa_5545-x_firmware = 9.12(2.12)`\n- `asa_5545-x_firmware = 9.13(0.33)`\n- `asa_5550_firmware = 9.12(2.12)`\n- `asa_5550_firmware = 9.13(0.33)`\n- `asa_5555-x_firmware = 9.12(2.12)`\n- `asa_5555-x_firmware = 9.13(0.33)`\n- `asa_5580_firmware = 9.12(2.12)`\n- `asa_5580_firmware = 9.13(0.33)`\n- `asa_5585-x_firmware = 9.12(2.12)`\n- `asa_5585-x_firmware = 9.13(0.33)`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `secure_firewall_threat_defense 6.4.0.9`","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":47.3,"likelihood":0.4,"exploitation":0,"ransomware":0},"changes":[]}