{"id":"CVE-2026-20197","aliases":["EUVD-2026-107376","GHSA-3wgh-x32w-jgcc"],"status":"published","title":"Multiple Cisco Products Snort 3 Teredo Protocol Denial of Service Vulnerability","description":"Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.\r\n\r\nThis vulnerability is due to incomplete error checking when Snort 3 parses Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.","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":"2026-11-08","score":0.00495,"percentile":0.42718,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-119"],"published":"2026-10-21T16:12:40Z","modified":"2026-10-22T19:11:21Z","products":[{"vendor":"cisco","product":"cisco open source snort3"},{"vendor":"cisco","product":"cisco secure firewall threat defense (ftd) software"},{"vendor":"cisco","product":"cisco utd snort ips engine software"}],"references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-misc-dos-6mB22qAK"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20197"},{"url":"https://github.com/advisories/GHSA-3wgh-x32w-jgcc"}],"sources":{"cve":[{"id":"CVE-2026-20197","title":"Multiple Cisco Products Snort 3 Teredo Protocol Denial of Service Vulnerability","description":"Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.\r\n\r\nThis vulnerability is due to incomplete error checking when Snort 3 parses Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.","status":"published","published":"2026-10-21T16:12:40.477Z","modified":"2026-10-22T19:11:21.691Z","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-119"],"updated_at":"2026-11-02T13:35:44.571002Z"}],"euvd":[{"id":"EUVD-2026-107376","description":"Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.\r\n\r\nThis vulnerability is due to incomplete error checking when Snort 3 parses Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.","status":"published","published":"2026-10-21T16:12:40Z","modified":"2026-10-22T19:11:21Z","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":"2026-11-02T16:59:34.021826Z"}],"ghsa":[{"id":"GHSA-3wgh-x32w-jgcc","title":"Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo Detection Engine...","description":"Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.\n\nThis vulnerability is due to incomplete error checking when Snort 3 parses Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.","status":"published","published":"2026-10-21T18:33:17Z","modified":"2026-10-21T18:33:23Z","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"}],"cwes":["CWE-119"],"updated_at":"2026-11-02T15:14:13.106716Z"}],"nvd":[{"id":"CVE-2026-20197","description":"Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.\r\n\r\nThis vulnerability is due to incomplete error checking when Snort 3 parses Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.","status":"published","published":"2026-10-21T17:18:27.543Z","modified":"2026-10-22T14:17:40.523Z","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-119"],"updated_at":"2026-11-02T14:13:02.371082Z"}]}}