{"id":"CVE-2020-3555","aliases":["EUVD-2020-24826","GHSA-r7x6-g4f2-fq99"],"status":"published","title":"Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SIP Denial of Service Vulnerability","description":"A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. An attacker could exploit this vulnerability by sending a high rate of crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a watchdog timeout and crash, resulting in a crash and reload of the affected device.","severity":{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.01696,"percentile":0.77354,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-404"],"published":"2020-10-21T18:41:28Z","modified":"2026-08-11T19:37:30Z","products":[{"vendor":"cisco","product":"adaptive_security_appliance"},{"vendor":"cisco","product":"adaptive_security_appliance_software"},{"vendor":"cisco","product":"cisco adaptive security appliance (asa) software"},{"vendor":"cisco","product":"secure_firewall_threat_defense"}],"references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-sipdos-3DGvdjvg","tags":["vendor-advisory","x_refsource_CISCO","x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-3555"},{"url":"https://github.com/advisories/GHSA-r7x6-g4f2-fq99"}],"sources":{"cve":[{"id":"CVE-2020-3555","title":"Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SIP Denial of Service Vulnerability","description":"A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. An attacker could exploit this vulnerability by sending a high rate of crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a watchdog timeout and crash, resulting in a crash and reload of the affected device.","status":"published","published":"2020-10-21T18:41:28.381Z","modified":"2024-11-13T17:45:33.271Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-404"],"updated_at":"2026-11-02T14:35:51.923913Z"}],"euvd":[{"id":"EUVD-2020-24826","description":"A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. An attacker could exploit this vulnerability by sending a high rate of crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a watchdog timeout and crash, resulting in a crash and reload of the affected device.","status":"published","published":"2020-10-21T18:41:28Z","modified":"2024-11-13T17:45:33Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T00:05:02.084189Z"}],"ghsa":[{"id":"GHSA-r7x6-g4f2-fq99","title":"A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software...","description":"A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. An attacker could exploit this vulnerability by sending a high rate of crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a watchdog timeout and crash, resulting in a crash and reload of the affected device.","status":"published","published":"2022-05-24T17:31:47Z","modified":"2023-08-16T18:30:20Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-404"],"updated_at":"2026-11-02T14:54:45.250925Z"}],"nvd":[{"id":"CVE-2020-3555","description":"A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. An attacker could exploit this vulnerability by sending a high rate of crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a watchdog timeout and crash, resulting in a crash and reload of the affected device.","status":"published","published":"2020-10-21T19:15:17.513Z","modified":"2026-08-11T19:37:30.88Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":7.8,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:C","level":"high","assessor":"primary"}],"cwes":["CWE-404"],"updated_at":"2026-11-02T14:06:20.704992Z"}]}}