CVE-2026-20052: Cisco Secure Firewall Threat Defense

Medium severity, CVSS 5.8. EPSS: 0.4% chance of exploitation in the next 30 days.

A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart. This vulnerability is due to a logic error in memory management when a device is performing Snort 3 SSL packet inspection. An attacker could exploit this vulnerability by sending crafted SSL packets through an established connection to be parsed by the Snort 3 Detection Engine. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.

Affected products

• Cisco Secure Firewall Threat Defense: version 7.4.0 only; version 7.4.1 only; version 7.4.1.1 only; version 7.4.2 only; version 7.4.2.1 only; version 7.6.0 only

Published 2026-03-04. Last modified 2026-08-20.