CVE-2022-20746: Cisco Secure Firewall Threat Defense

High severity, CVSS 7.5. EPSS: 1.4% chance of exploitation in the next 30 days.

A vulnerability in the TCP proxy functionality of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper handling of TCP flows. An attacker could exploit this vulnerability by sending a crafted stream of TCP traffic through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Affected products

• Cisco Secure Firewall Threat Defense: before 6.4.0.15 (fixed in 6.4.0.15); from 6.5.0, before 6.6.5.2 (fixed in 6.6.5.2); from 7.0.0, before 7.0.2 (fixed in 7.0.2); version 7.1.0 only

Published 2022-05-03. Last modified 2026-08-11.