{"id":"CVE-2026-20221","published":"2026-10-21T17:18:27.947","lastModified":"2026-10-22T14:17:40.940","description":"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.","cvssScore":5.8,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","cwes":["CWE-476"],"vendors":[],"products":[],"references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-gre-JNpMHrTv","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}