CVE-2020-3189: Cisco ASA 5505 Firmware

High severity, CVSS 8.6. EPSS: 1.9% chance of exploitation in the next 30 days.

A vulnerability in the VPN System Logging functionality for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak that can deplete system memory over time, which can cause unexpected system behaviors or device crashes. The vulnerability is due to the system memory not being properly freed for a VPN System Logging event generated when a VPN session is created or deleted. An attacker could exploit this vulnerability by repeatedly creating or deleting a VPN tunnel connection, which could leak a small amount of system memory for each logging event. A successful exploit could allow the attacker to cause system memory depletion, which can lead to a systemwide denial of service (DoS) condition. The attacker does not have any control of whether VPN System Logging is configured or not on the device, but it is enabled by default.

Affected products

• Cisco ASA 5505 Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5510 Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5512-X Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5515-X Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5520 Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5525-X Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5540 Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5545-X Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5550 Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5555-X Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5580 Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco ASA 5585-X Firmware: version 9.9(2) only; version 9.9(2.21) only; version 9.9(2.52) only; version 9.9(2.55) only
• Cisco Secure Firewall Threat Defense: version 6.2.3.12 only; version 6.2.3.13 only; version 6.2.3.14 only; version 6.2.3.15 only

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