Vulnerability · Published Oct 21, 2026 · Assigned by cisco
CVE-2026-20218Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
Medium 5.8
In plain English
A medium-severity stack buffer overflow 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 0.6% (higher than 50% of all known vulnerabilities).
Official description
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.
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 | 7.2.07.2.0.17.2.17.3.07.2.27.2.37.3.17.2.4 |
| 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-121 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L