{"schema":"threatline.record/2","record":{"id":"CVE-2026-20221","aliases":[],"summary":"Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities","details":"Multiple Cisco products are affected by a vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause an unexpected restart of the Snort 3 Detection Engine.\r\n\r\nThis vulnerability is due to improper handling of nested GRE traffic. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 Detection Engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. For more information, see the  section of this advisory. The Snort 3 Detection Engine will restart automatically. No manual intervention is required.","categories":["Network & edge"],"product":"Cisco Cyber Vision","vendor":"Cisco","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-20221","source_modified_at":"2026-10-22T19:11:26.546Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Cisco Cyber Vision","vendor":"Cisco","versions":[{"version":"3.0.0","status":"affected"},{"version":"3.0.2","status":"affected"},{"version":"3.0.3","status":"affected"},{"version":"3.0.1","status":"affected"},{"version":"3.1.0","status":"affected"},{"version":"3.0.4","status":"affected"},{"version":"3.1.1","status":"affected"},{"version":"3.1.2","status":"affected"},{"version":"3.2.0","status":"affected"},{"version":"3.0.5","status":"affected"},{"version":"3.2.1","status":"affected"},{"version":"3.0.6","status":"affected"},{"version":"3.2.2","status":"affected"},{"version":"3.2.3","status":"affected"},{"version":"3.2.4","status":"affected"},{"version":"4.0.0","status":"affected"},{"version":"4.0.1","status":"affected"},{"version":"4.0.2","status":"affected"},{"version":"4.0.3","status":"affected"},{"version":"4.1.0","status":"affected"},{"version":"4.1.1","status":"affected"},{"version":"4.1.2","status":"affected"},{"version":"4.1.3","status":"affected"},{"version":"4.1.4","status":"affected"},{"version":"4.2.0","status":"affected"},{"version":"4.2.1","status":"affected"},{"version":"4.1.5","status":"affected"},{"version":"4.2.2","status":"affected"},{"version":"4.2.X","status":"affected"},{"version":"4.2.3","status":"affected"}],"defaultStatus":"unknown"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-20221","source_modified_at":"2026-10-22T19:11:26.546Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Cisco Open Source Snort3","vendor":"Cisco","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"}],"defaultStatus":"unknown"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-20221","source_modified_at":"2026-10-22T19:11:26.546Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Cisco Secure Firewall Threat Defense (FTD) Software","vendor":"Cisco","versions":[{"version":"7.0.0","status":"affected"},{"version":"7.0.0.1","status":"affected"},{"version":"7.0.1","status":"affected"},{"version":"7.0.1.1","status":"affected"},{"version":"7.0.2","status":"affected"},{"version":"7.2.0","status":"affected"},{"version":"7.0.2.1","status":"affected"},{"version":"7.0.3","status":"affected"},{"version":"7.2.0.1","status":"affected"},{"version":"7.0.4","status":"affected"},{"version":"7.2.1","status":"affected"},{"version":"7.0.5","status":"affected"},{"version":"7.3.0","status":"affected"},{"version":"7.2.2","status":"affected"},{"version":"7.2.3","status":"affected"},{"version":"7.3.1","status":"affected"},{"version":"7.2.4","status":"affected"},{"version":"7.0.6","status":"affected"},{"version":"7.2.5","status":"affected"},{"version":"7.2.4.1","status":"affected"},{"version":"7.3.1.1","status":"affected"},{"version":"7.4.0","status":"affected"},{"version":"7.0.6.1","status":"affected"},{"version":"7.2.5.1","status":"affected"},{"version":"7.4.1","status":"affected"},{"version":"7.2.6","status":"affected"},{"version":"7.0.6.2","status":"affected"},{"version":"7.4.1.1","status":"affected"},{"version":"7.2.7","status":"affected"},{"version":"7.2.5.2","status":"affected"}],"defaultStatus":"unknown"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-20221","source_modified_at":"2026-10-22T19:11:26.546Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Cisco Umbrella Insights Virtual Appliance","vendor":"Cisco","versions":[{"version":"2.6.0","status":"affected"},{"version":"2.5.6","status":"affected"},{"version":"2.5","status":"affected"},{"version":"2.4.12","status":"affected"},{"version":"2.7","status":"affected"},{"version":"2.6.2","status":"affected"},{"version":"2.5.5","status":"affected"},{"version":"2.5.4","status":"affected"},{"version":"2.8","status":"affected"},{"version":"2.6.1","status":"affected"},{"version":"2.5.7","status":"affected"},{"version":"1.5.4","status":"affected"},{"version":"1.5.5","status":"affected"},{"version":"1.5.6","status":"affected"},{"version":"2.0.0","status":"affected"},{"version":"2.0.2","status":"affected"},{"version":"2.0.3","status":"affected"},{"version":"2.1.0","status":"affected"},{"version":"2.1.2","status":"affected"},{"version":"2.1.4","status":"affected"},{"version":"2.1.5","status":"affected"},{"version":"2.2","status":"affected"},{"version":"2.2.1","status":"affected"},{"version":"2.3","status":"affected"},{"version":"2.3.1","status":"affected"},{"version":"2.4","status":"affected"},{"version":"2.4.4","status":"affected"},{"version":"2.4.6","status":"affected"},{"version":"2.8.9","status":"affected"},{"version":"3.0","status":"affected"}],"defaultStatus":"unknown"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-20221","source_modified_at":"2026-10-22T19:11:26.546Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Cisco UTD SNORT IPS Engine Software","vendor":"Cisco","versions":[{"version":"3.17.1S","status":"affected"},{"version":"16.12.3","status":"affected"},{"version":"Fuji-16.9.5","status":"affected"},{"version":"16.12.4","status":"affected"},{"version":"17.3.1a","status":"affected"},{"version":"16.6.6","status":"affected"},{"version":"16.12.2","status":"affected"},{"version":"Fuji-16.9.6","status":"affected"},{"version":"3.17.0S","status":"affected"},{"version":"Fuji-16.9.3","status":"affected"},{"version":"Denali-16.3.7","status":"affected"},{"version":"Fuji-16.9.2","status":"affected"},{"version":"Fuji-16.9.4","status":"affected"},{"version":"Everest-16.6.4","status":"affected"},{"version":"Everest-16.6.3","status":"affected"},{"version":"16.6.5","status":"affected"},{"version":"Denali-16.3.5","status":"affected"},{"version":"17.2.1r","status":"affected"},{"version":"17.1.1","status":"affected"},{"version":"Everest-16.6.2","status":"affected"},{"version":"16.6.7a","status":"affected"},{"version":"Denali-16.3.4","status":"affected"},{"version":"16.6.1","status":"affected"},{"version":"Denali-16.3.9","status":"affected"},{"version":"Denali-16.3.3","status":"affected"},{"version":"16.12.1a","status":"affected"},{"version":"17.3.2","status":"affected"},{"version":"17.4.1a","status":"affected"},{"version":"16.12.5","status":"affected"},{"version":"17.5.1","status":"affected"}],"defaultStatus":"unknown"}],"fixed_versions":[],"cvss":5.8,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00454,"percentile":0.38454,"score_date":"2026-10-23"},"published_at":"2026-10-21T16:12:53.435Z","modified_at":"2026-10-22T19:11:26.546Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-20221","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-22T19:11:26.546Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-20221","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-gre-JNpMHrTv"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"partial","assessed_at":"2026-10-22T13:23:54.810399Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-22T19:11:26.546Z","content_hash":"fa55bf787daf8d6355784f2cc8895f21899f39f2ef0a8180c79d1e26a0cf39a4"}}