Vulnerability · Published Oct 21, 2026 · Assigned by cisco
CVE-2026-20019Multiple Cisco Products Snort 3 Netflow Denial of Service Vulnerabilities
Medium 5.8
In plain English
A medium-severity infinite loop in Cisco Open Source Snort3 from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).
Official description
Multiple Cisco products are affected by a vulnerability in the Snort 3 NetFlow 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 UDP Netflow Protocol packets. An attacker could exploit this vulnerability by sending a single crafted Netflow packet through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Open Source Snort3 | 3.12.2.03.1.2.03.1.3.03.1.4.03.1.5.03.1.6.03.1.7.03.1.8.0 |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.0.07.0.0.17.0.17.0.1.17.0.27.2.07.0.2.17.0.3 |
| Cisco | Cisco UTD SNORT IPS Engine Software | 17.12.1a17.12.217.13.1a17.12.317.14.1a17.12.417.12.3a17.15.1a |
Weakness: CWE-835 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L