{"id":"CVE-2026-20019","state":"PUBLISHED","title":"Multiple Cisco Products Snort 3 Netflow Denial of Service Vulnerabilities","description":"Multiple Cisco products are affected by a vulnerability in the Snort 3 NetFlow 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 UDP Netflow Protocol packets. An attacker could exploit this vulnerability by sending a single crafted Netflow packet through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.","publishedAt":"2026-10-21T16:12:20.285Z","updatedAt":"2026-10-22T19:10:53.022Z","severity":{"score":5.8,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","source":"cisco"},"assigner":"cisco","products":["Cisco Cisco Open Source Snort3","Cisco Cisco Secure Firewall Threat Defense (FTD) Software","Cisco Cisco UTD SNORT IPS Engine Software"],"affected":[{"vendor":"Cisco","product":"Cisco Open Source Snort3","defaultStatus":"unknown","versions":[{"version":"3.12.2.0","status":"affected"},{"version":"3.1.2.0","status":"affected"},{"version":"3.1.3.0","status":"affected"},{"version":"3.1.4.0","status":"affected"},{"version":"3.1.5.0","status":"affected"},{"version":"3.1.6.0","status":"affected"},{"version":"3.1.7.0","status":"affected"},{"version":"3.1.8.0","status":"affected"},{"version":"3.1.9.0","status":"affected"},{"version":"3.1.10.0","status":"affected"},{"version":"3.1.12.0","status":"affected"},{"version":"3.1.13.0","status":"affected"},{"version":"3.1.14.0","status":"affected"},{"version":"3.1.15.0","status":"affected"},{"version":"3.1.16.0","status":"affected"},{"version":"3.1.17.0","status":"affected"},{"version":"3.1.18.0","status":"affected"},{"version":"3.1.19.0","status":"affected"},{"version":"3.1.20.0","status":"affected"},{"version":"3.1.21.0","status":"affected"},{"version":"3.1.22.0","status":"affected"},{"version":"3.1.23.0","status":"affected"},{"version":"3.1.24.0","status":"affected"},{"version":"3.1.25.0","status":"affected"},{"version":"3.1.27.0","status":"affected"},{"version":"3.1.28.0","status":"affected"},{"version":"3.1.29.0","status":"affected"},{"version":"3.1.30.0","status":"affected"},{"version":"3.1.31.0","status":"affected"},{"version":"3.1.32.0","status":"affected"},{"version":"3.1.36.0","status":"affected"},{"version":"3.1.38.0","status":"affected"},{"version":"3.1.39.0","status":"affected"},{"version":"3.1.40.0","status":"affected"},{"version":"3.1.41.0","status":"affected"},{"version":"3.1.42.0","status":"affected"},{"version":"3.1.43.0","status":"affected"},{"version":"3.1.45.0","status":"affected"},{"version":"3.1.47.0","status":"affected"},{"version":"3.1.48.0","status":"affected"},{"version":"3.1.50.0","status":"affected"},{"version":"3.1.51.0","status":"affected"},{"version":"3.1.52.0","status":"affected"},{"version":"3.1.53.0","status":"affected"},{"version":"3.1.55.0","status":"affected"},{"version":"3.1.56.0","status":"affected"},{"version":"3.1.57.0","status":"affected"},{"version":"3.1.58.0","status":"affected"},{"version":"3.1.59.0","status":"affected"},{"version":"3.1.60.0","status":"affected"},{"version":"3.1.61.0","status":"affected"},{"version":"3.1.62.0","status":"affected"},{"version":"3.1.63.0","status":"affected"},{"version":"3.1.64.0","status":"affected"},{"version":"3.1.65.0","status":"affected"},{"version":"3.1.66.0","status":"affected"},{"version":"3.1.67.0","status":"affected"},{"version":"3.1.69.0","status":"affected"},{"version":"3.1.70.0","status":"affected"},{"version":"3.1.71.0","status":"affected"},{"version":"3.1.72.0","status":"affected"},{"version":"3.1.73.0","status":"affected"},{"version":"3.1.74.0","status":"affected"},{"version":"3.1.75.0","status":"affected"},{"version":"3.1.76.0","status":"affected"},{"version":"3.1.77.0","status":"affected"},{"version":"3.1.78.0","status":"affected"},{"version":"3.1.81.0","status":"affected"},{"version":"3.1.82.0","status":"affected"},{"version":"3.1.83.0","status":"affected"},{"version":"3.1.84.0","status":"affected"},{"version":"3.2.1.0","status":"affected"},{"version":"3.2.2.0","status":"affected"},{"version":"3.3.0.0","status":"affected"},{"version":"3.3.1.0","status":"affected"},{"version":"3.3.2.0","status":"affected"},{"version":"3.3.3.0","status":"affected"},{"version":"3.3.4.0","status":"affected"},{"version":"3.3.5.0","status":"affected"},{"version":"3.3.7.0","status":"affected"},{"version":"3.5.0.0","status":"affected"},{"version":"3.5.1.0","status":"affected"},{"version":"3.8.1.0","status":"affected"},{"version":"3.6.0.0","status":"affected"},{"version":"3.6.2.0","status":"affected"},{"version":"3.9.3.0","status":"affected"},{"version":"3.7.2.0","status":"affected"},{"version":"3.7.0.0","status":"affected"},{"version":"3.9.6.0","status":"affected"},{"version":"3.10.0.0","status":"affected"},{"version":"3.10.2.0","status":"affected"},{"version":"3.7.4.0","status":"affected"},{"version":"3.9.0.0","status":"affected"},{"version":"3.5.2.0","status":"affected"},{"version":"3.12.1.0","status":"affected"},{"version":"3.6.1.0","status":"affected"},{"version":"3.9.2.0","status":"affected"},{"version":"3.6.3.0","status":"affected"},{"version":"3.9.5.0","status":"affected"},{"version":"3.7.1.0","status":"affected"},{"version":"3.9.7.0","status":"affected"},{"version":"3.7.3.0","status":"affected"},{"version":"3.10.1.0","status":"affected"},{"version":"3.9.1.0","status":"affected"},{"version":"3.11.1.0","status":"affected"}]},{"vendor":"Cisco","product":"Cisco 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An attacker could exploit this vulnerability by sending a single crafted Netflow packet through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition."}],"affected":[{"vendor":"Cisco","product":"Cisco Open Source 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