CVE-2020-3303: Cisco Adaptive Security Appliance

High severity, CVSS 7.5. EPSS: 1.2% chance of exploitation in the next 30 days.

A vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper management of system memory. An attacker could exploit this vulnerability by sending malicious IKEv1 traffic to an affected device. A successful exploit could allow the attacker to cause a DoS condition on the affected device.

Affected products

• Cisco Adaptive Security Appliance: before 9.6.4.36 (fixed in 9.6.4.36)
• Cisco Adaptive Security Appliance Software: from 9.7, before 9.8.4.10 (fixed in 9.8.4.10); from 9.9, before 9.10.1.30 (fixed in 9.10.1.30); from 9.12, before 9.12.2.9 (fixed in 9.12.2.9)
• Cisco Secure Firewall Threat Defense: before 6.3.0.5 (fixed in 6.3.0.5); from 6.4.0, before 6.4.0.6 (fixed in 6.4.0.6)

Published 2020-05-06. Last modified 2026-08-11.