What’s Vulnerable › Vulnerabilities
CVE-2026-20218: Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
- Severity: medium (CVSS 5.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.6% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-21 · updated 2026-10-22
- Weakness: CWE-121
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
- Cisco Open Source Snort3: 3.12.2.0, 3.1.2.0, 3.1.3.0, 3.1.4.0, 3.1.5.0, 3.1.6.0 (+99)
- Cisco Firepower Threat Defense Software: 7.2.0, 7.2.0.1, 7.2.1, 7.3.0, 7.2.2, 7.2.3 (+37)
- Cisco UTD SNORT IPS Engine Software: 17.12.1a, 17.12.2, 17.13.1a, 17.12.3, 17.14.1a, 17.12.4 (+32)
In the news
- Multiple Cisco Products Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
- ZDI-26-788: Cisco Snort OLE VBA Decompression Stack-based Buffer Overflow Remote Code Execution Vulnerability
- Cisco Advance Notification for Publication of October 21, 2026, Security Advisories
References
Get alerted when CVE-2026-20218 or the next vulnerability affects your stack