Answer in brief
CVE-2026-20019 records a Medium severity (CVSS 5.8) vulnerability in Multiple Cisco Products Snort 3 Netflow Denial of Service Vulnerabilities. The current sources do not mark it as known exploited. The current feed maps Cisco/Cisco Open Source Snort3 (generic), Cisco/Cisco Secure Firewall Threat Defense (FTD) Software (generic), Cisco/Cisco UTD SNORT IPS Engine Software (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Cisco/Cisco Open Source Snort3 (generic), Cisco/Cisco Secure Firewall Threat Defense (FTD) Software (generic), Cisco/Cisco UTD SNORT IPS Engine Software (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Cisco/Cisco Open Source Snort3generic | 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 | Not reported |
| Cisco/Cisco Secure Firewall Threat Defense (FTD) Softwaregeneric | 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 | Not reported |
| Cisco/Cisco UTD SNORT IPS Engine Softwaregeneric | 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 || 17.15.6 || 17.18.4 || 26.1.2 | Not reported |
Published upstream
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 21, 2026
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.
Quoted source text, attributed separately from HOL analysis.