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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Cisco Cisco Open Source Snort3 unknown
Version Status Constraints
3.12.2.0 affected —
3.1.2.0 affected —
3.1.3.0 affected —
3.1.4.0 affected —
3.1.5.0 affected —
3.1.6.0 affected —
3.1.7.0 affected —
3.1.8.0 affected —
3.1.9.0 affected —
3.1.10.0 affected —
3.1.12.0 affected —
3.1.13.0 affected —
3.1.14.0 affected —
3.1.15.0 affected —
3.1.16.0 affected —
3.1.17.0 affected —
3.1.18.0 affected —
3.1.19.0 affected —
3.1.20.0 affected —
3.1.21.0 affected —
3.1.22.0 affected —
3.1.23.0 affected —
3.1.24.0 affected —
3.1.25.0 affected —
3.1.27.0 affected —
3.1.28.0 affected —
3.1.29.0 affected —
3.1.30.0 affected —
3.1.31.0 affected —
3.1.32.0 affected —
3.1.36.0 affected —
3.1.38.0 affected —
3.1.39.0 affected —
3.1.40.0 affected —
3.1.41.0 affected —
3.1.42.0 affected —
3.1.43.0 affected —
3.1.45.0 affected —
3.1.47.0 affected —
3.1.48.0 affected —
3.1.50.0 affected —
3.1.51.0 affected —
3.1.52.0 affected —
3.1.53.0 affected —
3.1.55.0 affected —
3.1.56.0 affected —
3.1.57.0 affected —
3.1.58.0 affected —
3.1.59.0 affected —
3.1.60.0 affected —
3.1.61.0 affected —
3.1.62.0 affected —
3.1.63.0 affected —
3.1.64.0 affected —
3.1.65.0 affected —
3.1.66.0 affected —
3.1.67.0 affected —
3.1.69.0 affected —
3.1.70.0 affected —
3.1.71.0 affected —
3.1.72.0 affected —
3.1.73.0 affected —
3.1.74.0 affected —
3.1.75.0 affected —
3.1.76.0 affected —
3.1.77.0 affected —
3.1.78.0 affected —
3.1.81.0 affected —
3.1.82.0 affected —
3.1.83.0 affected —
3.1.84.0 affected —
3.2.1.0 affected —
3.2.2.0 affected —
3.3.0.0 affected —
3.3.1.0 affected —
3.3.2.0 affected —
3.3.3.0 affected —
3.3.4.0 affected —
3.3.5.0 affected —
3.3.7.0 affected —
3.5.0.0 affected —
3.5.1.0 affected —
3.8.1.0 affected —
3.6.0.0 affected —
3.6.2.0 affected —
3.9.3.0 affected —
3.7.2.0 affected —
3.7.0.0 affected —
3.9.6.0 affected —
3.10.0.0 affected —
3.10.2.0 affected —
3.7.4.0 affected —
3.9.0.0 affected —
3.5.2.0 affected —
3.12.1.0 affected —
3.6.1.0 affected —
3.9.2.0 affected —
3.6.3.0 affected —
3.9.5.0 affected —
3.7.1.0 affected —
3.9.7.0 affected —
3.7.3.0 affected —
3.10.1.0 affected —
3.9.1.0 affected —
3.11.1.0 affected —
Cisco Cisco Secure Firewall Threat Defense (FTD) Software unknown
Version Status Constraints
7.0.0 affected —
7.0.0.1 affected —
7.0.1 affected —
7.0.1.1 affected —
7.0.2 affected —
7.2.0 affected —
7.0.2.1 affected —
7.0.3 affected —
7.2.0.1 affected —
7.0.4 affected —
7.2.1 affected —
7.0.5 affected —
7.3.0 affected —
7.2.2 affected —
7.2.3 affected —
7.3.1 affected —
7.2.4 affected —
7.0.6 affected —
7.2.5 affected —
7.2.4.1 affected —
7.3.1.1 affected —
7.4.0 affected —
7.0.6.1 affected —
7.2.5.1 affected —
7.4.1 affected —
7.2.6 affected —
7.0.6.2 affected —
7.4.1.1 affected —
7.2.7 affected —
7.2.5.2 affected —
7.3.1.2 affected —
7.2.8 affected —
7.6.0 affected —
7.4.2 affected —
7.2.8.1 affected —
7.0.6.3 affected —
7.4.2.1 affected —
7.2.9 affected —
7.0.7 affected —
7.7.0 affected —
7.4.2.2 affected —
7.2.10 affected —
7.6.1 affected —
7.4.2.3 affected —
7.0.8 affected —
7.6.2 affected —
7.7.10 affected —
7.7.11 affected —
7.0.8.1 affected —
7.6.2.1 affected —
7.7.10.1 affected —
7.4.2.4 affected —
7.2.10.2 affected —
7.4.3 affected —
7.6.4 affected —
10.0.0 affected —
7.4.4 affected —
7.0.9 affected —
7.2.11 affected —
7.4.7 affected —
Cisco Cisco UTD SNORT IPS Engine Software unknown
Version Status Constraints
17.12.1a affected —
17.12.2 affected —
17.13.1a affected —
17.12.3 affected —
17.14.1a affected —
17.12.4 affected —
17.12.3a affected —
17.15.1a affected —
17.16.1a affected —
17.12.4a affected —
17.15.2c affected —
17.12.4b affected —
17.15.2a affected —
17.12.5 affected —
17.17.1 affected —
17.12.5a affected —
17.15.3a affected —
17.15.3 affected —
17.12.5b affected —
17.12.5c affected —
17.15.4 affected —
17.18.1 affected —
17.18.1a affected —
17.12.6 affected —
17.15.4c affected —
17.12.5d affected —
17.18.2 affected —
26.1.1 affected —
17.15.5 affected —
17.15.5a affected —
17.12.7 affected —
17.12.7a affected —
17.12.7b affected —
17.18.3a affected —
17.12.8 affected —
17.15.6 affected —
17.18.4 affected —
26.1.2 affected —

No data.

No data.

No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-misc-dos-6mB22qAK cve-icon cve-icon
History

Wed, 21 Oct 2026 17:15:00 +0000

Type Values Removed Values Added
Description 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.
Title Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities
Weaknesses CWE-128
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L'}

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2026-10-21T16:12:29.897Z

Reserved: 2025-10-08T11:59:15.393Z

Link: CVE-2026-20179

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-21T17:18:27.340

Modified: 2026-10-21T18:54:37.403

Link: CVE-2026-20179

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses