Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
Summary
| CVE | CVE-2026-20218 |
|---|---|
| State | PUBLISHED |
| Assigner | cisco |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-21 17:18:27 UTC |
| Updated | 2026-10-22 19:17:51 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 5.8 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
EPSS: 0.004160000 probability, percentile 0.348190000 (date 2026-10-22)
Problem Types: CWE-121 | CWE-121 Stack-based Buffer Overflow
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 5.8 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L |
| 3.1 | CNA | CVSSV3_1 | 5.8 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
ChangedConfidentiality
NoneIntegrity
NoneAvailability
LowCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.12.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.3.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.4.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.5.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.6.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.7.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.8.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.9.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.10.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.12.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.13.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.14.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.15.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.16.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.17.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.18.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.19.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.20.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.21.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.22.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.23.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.24.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.25.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.27.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.28.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.29.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.30.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.31.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.32.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.36.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.38.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.39.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.40.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.41.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.42.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.43.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.45.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.47.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.48.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.50.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.51.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.52.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.53.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.55.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.56.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.57.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.58.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.59.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.60.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.61.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.62.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.63.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.64.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.65.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.66.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.67.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.69.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.70.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.71.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.72.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.73.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.74.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.75.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.76.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.77.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.78.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.81.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.82.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.83.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.1.84.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.2.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.2.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.3.0.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.3.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.3.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.3.3.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.3.4.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.3.5.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.3.7.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.5.0.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.5.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.8.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.6.0.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.6.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.9.3.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.7.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.7.0.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.9.6.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.10.0.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.10.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.7.4.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.9.0.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.5.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.12.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.6.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.9.2.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.6.3.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.9.5.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.7.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.9.7.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.7.3.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.10.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.9.1.0 | Not specified |
| CNA | Cisco | Cisco Open Source Snort3 | affected 3.11.1.0 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.0 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.0.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.3.0 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.2 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.3 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.3.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.4 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.5 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.4.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.3.1.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.0 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.5.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.6 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.1.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.7 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.5.2 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.3.1.2 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.8 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.6.0 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.2 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.8.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.2.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.9 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.7.0 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.2.2 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.10 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.6.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.2.3 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.6.2 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.7.10 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.7.11 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.6.2.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.7.10.1 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.2.4 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.10.2 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.3 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.6.4 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 10.0.0 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.4 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.2.11 | Not specified |
| CNA | Cisco | Cisco Secure Firewall Threat Defense FTD Software | affected 7.4.7 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.1a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.2 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.13.1a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.3 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.14.1a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.4 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.3a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.1a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.16.1a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.4a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.2c | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.4b | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.2a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.5 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.17.1 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.5a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.3a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.3 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.5b | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.5c | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.4 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.18.1 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.18.1a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.6 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.4c | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.5d | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.18.2 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 26.1.1 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.5 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.5a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.7 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.7a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.7b | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.18.3a | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.12.8 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.15.6 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 17.18.4 | Not specified |
| CNA | Cisco | Cisco UTD SNORT IPS Engine Software | affected 26.1.2 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3... | [email protected] | sec.cloudapps.cisco.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
Exploits
CNA: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
There are currently no legacy QID mappings associated with this CVE.