CVE-2022-20751: 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 Snort detection engine integration for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause unlimited memory consumption, which could lead to a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient memory management for certain Snort events. An attacker could exploit this vulnerability by sending a series of crafted IP packets that would generate specific Snort events on an affected device. A sustained attack could cause an out of memory condition on the affected device. A successful exploit could allow the attacker to interrupt all traffic flowing through the affected device. In some circumstances, the attacker may be able 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 7.1.0.0 only

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