CVE-2020-3188: Cisco ASA 5505 Firmware
Medium severity, CVSS 5.3. EPSS: 1.7% chance of exploitation in the next 30 days.
A vulnerability in how Cisco Firepower Threat Defense (FTD) Software handles session timeouts for management connections could allow an unauthenticated, remote attacker to cause a buildup of remote management connections to an affected device, which could result in a denial of service (DoS) condition. The vulnerability exists because the default session timeout period for specific to-the-box remote management connections is too long. An attacker could exploit this vulnerability by sending a large and sustained number of crafted remote management connections to an affected device, resulting in a buildup of those connections over time. A successful exploit could allow the attacker to cause the remote management interface or Cisco Firepower Device Manager (FDM) to stop responding and cause other management functions to go offline, resulting in a DoS condition. The user traffic that is flowing through the device would not be affected, and the DoS condition would be isolated to remote management only.
Affected products
- Cisco ASA 5505 Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5510 Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5512-X Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5515-X Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5520 Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5525-X Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5540 Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5545-X Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5550 Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5555-X Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5580 Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco ASA 5585-X Firmware: version 9.8(3) only; version 101.6(1.96) only
- Cisco Secure Firewall Threat Defense: from 6.4.0, before 6.4.0.9 (fixed in 6.4.0.9); from 6.5.0, before 6.5.0.5 (fixed in 6.5.0.5)
Published 2020-05-06. Last modified 2026-08-11.