CVE-2026-20197
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.
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| 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 | — |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.