Answer in brief
CVE-2026-20218 records a Medium severity (CVSS 5.8) vulnerability in Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability. 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 | 7.2.0 || 7.2.0.1 || 7.2.1 || 7.3.0 || 7.2.2 || 7.2.3 || 7.3.1 || 7.2.4 || 7.2.5 || 7.2.4.1 || 7.3.1.1 || 7.4.0 || 7.2.5.1 || 7.4.1 || 7.2.6 || 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 || 7.4.2.1 || 7.2.9 || 7.7.0 || 7.4.2.2 || 7.2.10 || 7.6.1 || 7.4.2.3 || 7.6.2 || 7.7.10 || 7.7.11 || 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 || 7.2.11 || 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
A vulnerability in the Snort 3 Visual Basic for Applications (VBA) Decompression Engine of multiple Cisco products could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper range checking when Snort 3 decompresses VBA data, which is user controlled. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine of a targeted device. A successful exploit could allow the attacker to cause an overflow of stack data, which could result in a DoS condition.
Quoted source text, attributed separately from HOL analysis.