🔐 CVE Alert

CVE-2026-20179

MEDIUM 5.8

Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities

CVSS Score
5.8
EPSS Score
0.0%
EPSS Percentile
0th

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.

CWE CWE-128
Vendor cisco
Product cisco open source snort3
Ecosystems
Industries
NetworkingTelecommunications
Published Oct 21, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low

Affected Versions

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

References

NVD ↗ CVE.org ↗ EPSS Data ↗
sec.cloudapps.cisco.com: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-misc-dos-6mB22qAK