CVE-2026-20179

Multiple Cisco products are affected by a vulnerability in the Snort 3 Generic Routing Encapsulation (GRE) 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. This vulnerability is due to incomplete error checking when Snort 3 parses GRE packets. An attacker could exploit this vulnerability by sending a crafted GRE 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.

CVSS v3 5.8 MEDIUM

5.8^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope CHANGED

References

Link	Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-misc-dos-6mB22qAK

Configurations

No configuration.

History

21 Oct 2026, 17:18

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-21 17:18

Updated : 2026-10-22 14:17

NVD link : CVE-2026-20179

Mitre link : CVE-2026-20179

CVE.ORG link : CVE-2026-20179

JSON object : View

Products Affected

No product.

CWE

CWE-128

Wrap-around Error

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"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"}, 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"versions": [{"status": "affected", "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", "version": "7.3.1.2"}, {"status": "affected", "version": "7.2.8"}, {"status": "affected", "version": "7.6.0"}, {"status": "affected", "version": "7.4.2"}, {"status": "affected", "version": "7.2.8.1"}, {"status": "affected", "version": "7.0.6.3"}, {"status": "affected", "version": "7.4.2.1"}, {"status": "affected", "version": "7.2.9"}, {"status": "affected", "version": "7.0.7"}, {"status": "affected", "version": "7.7.0"}, {"status": "affected", "version": "7.4.2.2"}, {"status": "affected", "version": "7.2.10"}, {"status": "affected", "version": "7.6.1"}, {"status": "affected", "version": "7.4.2.3"}, 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"version": "17.12.3"}, {"status": "affected", "version": "17.14.1a"}, {"status": "affected", "version": "17.12.4"}, {"status": "affected", "version": "17.12.3a"}, {"status": "affected", "version": "17.15.1a"}, {"status": "affected", "version": "17.16.1a"}, {"status": "affected", "version": "17.12.4a"}, {"status": "affected", "version": "17.15.2c"}, {"status": "affected", "version": "17.12.4b"}, {"status": "affected", "version": "17.15.2a"}, {"status": "affected", "version": "17.12.5"}, {"status": "affected", "version": "17.17.1"}, {"status": "affected", "version": "17.12.5a"}, {"status": "affected", "version": "17.15.3a"}, {"status": "affected", "version": "17.15.3"}, {"status": "affected", "version": "17.12.5b"}, {"status": "affected", "version": "17.12.5c"}, {"status": "affected", "version": "17.15.4"}, {"status": "affected", "version": "17.18.1"}, {"status": "affected", "version": "17.18.1a"}, {"status": "affected", "version": "17.12.6"}, {"status": "affected", "version": "17.15.4c"}, {"status": "affected", "version": "17.12.5d"}, {"status": "affected", "version": "17.18.2"}, {"status": "affected", "version": "26.1.1"}, {"status": "affected", "version": "17.15.5"}, {"status": "affected", "version": "17.15.5a"}, {"status": "affected", "version": "17.12.7"}, {"status": "affected", "version": "17.12.7a"}, {"status": "affected", "version": "17.12.7b"}, {"status": "affected", "version": "17.18.3a"}, {"status": "affected", "version": "17.12.8"}, {"status": "affected", "version": "17.15.6"}, {"status": "affected", "version": "17.18.4"}, {"status": "affected", "version": "26.1.2"}], "defaultStatus": "unknown"}]}], "published": "2026-10-21T17:18:27.340", "references": [{"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-misc-dos-6mB22qAK", "source": "psirt@cisco.com"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "psirt@cisco.com", "description": [{"lang": "en", "value": "CWE-128"}]}], "descriptions": [{"lang": "en", "value": "Multiple Cisco products are affected by a vulnerability in the Snort 3 Generic Routing Encapsulation (GRE) 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 GRE packets. An attacker could exploit this vulnerability by sending a crafted GRE 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."}], "lastModified": "2026-10-22T14:17:40.290", "sourceIdentifier": "psirt@cisco.com"}