CVE-2026-20179
Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities
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.
Weakness: CWE-128
Affected products
| Vendor | Product | Category | Matched by |
|---|---|---|---|
| Cisco | Cisco Firepower Threat Defense (FTD) Check your version | Firewall / NGFW | cna-assigner |
| Cisco | Cisco UTD SNORT IPS Engine | Threat Detection & Sandbox | cna-assigner |
Vendor-reported products (3)
- Cisco · Cisco Open Source Snort3
- Cisco · Cisco Secure Firewall Threat Defense (FTD) Software
- Cisco · Cisco UTD SNORT IPS Engine Software
Vendor advisory
cisco-sa-snort3-misc-dos-6mB22qAK
Multiple Cisco Products Snort 3 Denial of Service Vulnerabilities
Cisco’s rating: Medium (advisory CVSS 5.8) · Published Oct 21, 2026
Bug IDs: CSCwr25134 , CSCwu23999 , CSCwu51449 , CSCwu51451 , CSCwu53570
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from