CVE-2026-20197

MediumCVSS 5.8/10Last modified Oct 22, 2026

Description

Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo 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 Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo 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.

Metrics

CVSS 3.1 5.8/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Weakness enumeration

Affected software

Source: the vendor's advisory (CNA). NVD analysis pending.

VendorProductVersions
CiscoCisco Open Source Snort33.12.2.0; 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
CiscoCisco Secure Firewall Threat Defense (FTD) Software7.0.0; 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
CiscoCisco UTD SNORT IPS Engine Software17.12.1a; 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

References

Timeline

Published
Oct 21, 2026
Last modified
Oct 22, 2026
NVD status
Awaiting Analysis

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CVE-2026-20197: Medium severity, CVSS 5.8 | Vulnix