CVE-2026-20290: medium-severity vulnerability in Cisco Secure Firewall Threat Defense (FTD)…
Cisco Secure Firewall Threat Defense Software Snort 2 SSL/TLS Denial of Service Vulnerability
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.8epss 0.3%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Affected products
Cisco · Cisco Secure Firewall Threat Defense (FTD) SoftwareRelated CVEs — Cisco Secure Firewall Threat Defense (FTD)…
In the same product, most dangerous first.
CVE-2025-20362MEDIUMCVE-2025-20362EPSS 86.7%KEVCVE-2025-20333CRITICALCVE-2025-20333EPSS 72.0%KEVCVE-2026-20349HIGHCisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service VulnerabilityEPSS 1.0%KEVCVE-2026-76418HIGHCisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Tunnel Denial of Service VulnerabilityEPSS 0.8%KEVCVE-2024-20358MEDIUMCVE-2024-20358EPSS 0.7%CVE-2026-20135HIGHCisco Secure Firewall Threat Defense Software TLS 1.3 Denial of Service VulnerabilityEPSS 0.7%