CVE-2026-20218
Reported by cisco · Published October 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.
Risk Scores
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Open Source Snort3 | 3.12.2.0, 3.1.2.0, 3.1.3.0 |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.2.0, 7.2.0.1, 7.2.1 |
| Cisco | Cisco UTD SNORT IPS Engine Software | 17.12.1a, 17.12.2, 17.13.1a |
| Cisco | Cisco UTD SNORT IPS Engine Software | 17.12.1a, 17.12.2, 17.13.1a |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.6.4, 10.0.0, 7.2.0 |
| Cisco | Cisco Open Source Snort3 | 3.5.1.0, 3.8.1.0, 3.6.0.0 |
Timeline
- Oct 21, 2026 CVE Published
- Oct 22, 2026 EPSS Score
- Oct 22, 2026 Coalition ESS Score
- Oct 22, 2026 CVE Updated
- Oct 25, 2026 EPSS Score
- Oct 29, 2026 EPSS Score