Buffer overflow in Cisco Secure Firewall Threat Defense (Ftd) Software
CVE-2026-20218
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Cisco Secure Firewall Threat Defense (Ftd) Software — versions 10.0.0, 7.2.0, 7.2.0.1
- Cisco Utd Snort Ips Engine Software — versions 17.12.1a, 17.12.2, 17.12.3
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-20218?
- CVE-2026-20218 is a medium-severity vulnerability in Cisco Secure Firewall Threat Defense (Ftd) Software, classified under Stack-based Buffer Overflow. CVSS score: 5.8/10. Published 2026-10-21.
- How severe is CVE-2026-20218?
- Medium severity. CVSS v3 base score is 5.8 out of 10.