Description
Multiple Cisco products are affected by a vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause an unexpected restart of the Snort 3 Detection Engine.
This vulnerability is due to improper handling of nested GRE traffic. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 Detection Engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. For more information, see the section of this advisory. The Snort 3 Detection Engine will restart automatically. No manual intervention is required.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Cisco | Cisco Cyber Vision | 3.0.0, 3.0.2, 3.0.3, 3.0.1, 3.1.0, 3.0.4, 3.1.1, 3.1.2, 3.2.0, 3.0.5, 3.2.1, 3.0.6, 3.2.2, 3.2.3, 3.2.4, 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.1.0, 4.1.1, 4.1.2, 4.1.3, 4.1.4, 4.2.0, 4.2.1, 4.1.5, 4.2.2, 4.2.X, 4.2.3, 4.2.4, 4.2.6, 4.1.6, 4.3.0, 4.3.1, 4.3.2, 4.3.3, 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.1.7, 5.0.0… | — |
| 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.… | — |
| 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… | — |
| Cisco | Cisco Umbrella Insights Virtual Appliance | 2.6.0, 2.5.6, 2.5, 2.4.12, 2.7, 2.6.2, 2.5.5, 2.5.4, 2.8, 2.6.1, 2.5.7, 1.5.4, 1.5.5, 1.5.6, 2.0.0, 2.0.2, 2.0.3, 2.1.0, 2.1.2, 2.1.4, 2.1.5, 2.2, 2.2.1, 2.3, 2.3.1, 2.4, 2.4.4, 2.4.6, 2.8.9, 3.0, 3.1, 3.2, 2.8.1, 2.8.2, 2.8.3, 2.8.4, 2.8.5, 3.0.1, 3.0.2, 3.0.4, 3.0.5, 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3… | — |
| Cisco | Cisco UTD SNORT IPS Engine Software | 3.17.1S, 16.12.3, Fuji-16.9.5, 16.12.4, 17.3.1a, 16.6.6, 16.12.2, Fuji-16.9.6, 3.17.0S, Fuji-16.9.3, Denali-16.3.7, Fuji-16.9.2, Fuji-16.9.4, Everest-16.6.4, Everest-16.6.3, 16.6.5, Denali-16.3.5, 17.2.1r, 17.1.1, Everest-16.6.2, 16.6.7a, Denali-16.3.4, 16.6.1, Denali-16.3.9, Denali-16.3.3, 16.12.1… | — |
Advisories 2
- NCSC-2026-0450 Kwetsbaarheden verholpen in Snort 3 van Cisco NCSC-NL (Netherlands) · Oct 22, 2026
- WID-SEC-2026-4104 Cisco Produkte (IOS XE, SFTD) und Snort: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 21, 2026