{"id":"CVE-2026-20006","aliases":["EUVD-2026-9453","GHSA-mh5f-h37q-2qm8"],"status":"published","title":"Cisco Firepower Threat Defense Software and Cisco FirePOWER Services TLS with Snort 3 Denial of Service Vulnerability","description":"A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition.\u0026nbsp;\r\nNote: TLS 1.3 is not affected by this vulnerability.","severity":{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-07","score":0.00433,"percentile":0.37852,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-388"],"published":"2026-03-04T17:37:54Z","modified":"2026-08-20T16:45:55Z","products":[{"vendor":"cisco","product":"cisco secure firewall threat defense (ftd) software"},{"vendor":"cisco","product":"secure_firewall_threat_defense"}],"references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tcp-dos-rHfqnwRg","tags":["Vendor Advisory","Mitigation"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20006"},{"url":"https://github.com/advisories/GHSA-mh5f-h37q-2qm8"}],"sources":{"cve":[{"id":"CVE-2026-20006","title":"Cisco Firepower Threat Defense Software and Cisco FirePOWER Services TLS with Snort 3 Denial of Service Vulnerability","description":"A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition.\u0026nbsp;\r\nNote: TLS 1.3 is not affected by this vulnerability.","status":"published","published":"2026-03-04T17:37:54.866Z","modified":"2026-03-04T20:51:58.937Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-388"],"updated_at":"2026-11-02T13:35:44.571002Z"}],"euvd":[{"id":"EUVD-2026-9453","description":"A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition.\u0026nbsp;\r\nNote: TLS 1.3 is not affected by this vulnerability.","status":"published","published":"2026-03-04T17:37:54Z","modified":"2026-03-04T20:51:58Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T19:48:11.18109Z"}],"ghsa":[{"id":"GHSA-mh5f-h37q-2qm8","title":"A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco...","description":"A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition.\n\nThis vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition.\u0026nbsp;\nNote: TLS 1.3 is not affected by this vulnerability.","status":"published","published":"2026-03-04T18:31:54Z","modified":"2026-03-04T18:32:03Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:06:26.948991Z"}],"nvd":[{"id":"CVE-2026-20006","description":"A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition.\u0026nbsp;\r\nNote: TLS 1.3 is not affected by this vulnerability.","status":"published","published":"2026-03-04T18:16:13.803Z","modified":"2026-08-20T16:45:55.88Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-388"],"updated_at":"2026-11-02T14:12:07.420927Z"}]}}