CVE-2022-20760: Cisco Adaptive Security Appliance Software

High severity, CVSS 7.5. EPSS: 1.6% chance of exploitation in the next 30 days.

A vulnerability in the DNS inspection handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service condition (DoS) on an affected device. This vulnerability is due to a lack of proper processing of incoming requests. An attacker could exploit this vulnerability by sending crafted DNS requests at a high rate to an affected device. A successful exploit could allow the attacker to cause the device to stop responding, resulting in a DoS condition.

Affected products

• Cisco Adaptive Security Appliance Software: before 9.12.4.38 (fixed in 9.12.4.38); from 9.13.0, before 9.14.4 (fixed in 9.14.4); from 9.15.0, before 9.15.1.21 (fixed in 9.15.1.21); from 9.16.0, before 9.16.2.14 (fixed in 9.16.2.14); from 9.17.0, before 9.17.1.7 (fixed in 9.17.1.7)
• 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.