CVE-2026-20290
Cisco Secure Firewall Threat Defense Software Snort 2 SSL/TLS Denial of Service Vulnerability
Severity
Medium 5.8
CVSS 3.1
Exploited
Not listed
EPSS
0.002
8.9th percentile
Discovered by
Third party
Vendor-published field
Published
Sep 16, 2026
Assigned by cisco
Description
A vulnerability in SSL/TLS certificate parsing in the Snort 2 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 2 Detection Engine to restart. This vulnerability is due to incomplete validation of the SSL certificate. An attacker could exploit this vulnerability by sending a crafted SSL connection setup request to be parsed by Snort 2. A successful exploit could allow the attacker to cause the Snort 2 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.
Weakness: CWE-805
Affected products
| Vendor | Product | Category | Matched by |
|---|---|---|---|
| Cisco | Cisco Secure Firewall | Firewall / NGFW | cna-assigner |
Vendor-reported products (1)
- Cisco · Cisco Secure Firewall Threat Defense (FTD) Software