CVE-2022-20854: Cisco Secure Firewall Management Center

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

A vulnerability in the processing of SSH connections of Cisco Firepower Management Center (FMC) and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper error handling when an SSH session fails to be established. An attacker could exploit this vulnerability by sending a high rate of crafted SSH connections to the instance. A successful exploit could allow the attacker to cause resource exhaustion, resulting in a reboot on the affected device.

Affected products

• Cisco Secure Firewall Management Center: from 6.1.0, up to and including 6.1.0.7; from 6.2.0, up to and including 6.2.0.6; from 6.2.2, up to and including 6.2.2.5; from 6.2.3, up to and including 6.2.3.18; from 6.3.0, up to and including 6.3.0.5; from 6.4.0, up to and including 6.4.0.15; …
• Cisco Secure Firewall Threat Defense: from 6.1.0, up to and including 6.1.0.7; from 6.2.0, up to and including 6.2.0.6; from 6.2.2, up to and including 6.2.2.5; from 6.2.3, up to and including 6.2.3.18; from 6.3.0, up to and including 6.3.0.5; from 6.4.0, up to and including 6.4.0.15; …

Published 2022-11-15. Last modified 2026-08-11.