CVE-2020-3196: Cisco Adaptive Security Appliance Software

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

A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust memory resources on the affected device, leading to a denial of service (DoS) condition. The vulnerability is due to improper resource management for inbound SSL/TLS connections. An attacker could exploit this vulnerability by establishing multiple SSL/TLS connections with specific conditions to the affected device. A successful exploit could allow the attacker to exhaust the memory on the affected device, causing the device to stop accepting new SSL/TLS connections and resulting in a DoS condition for services on the device that process SSL/TLS traffic. Manual intervention is required to recover an affected device.

Affected products

Cisco Adaptive Security Appliance Software: from 9.6, before 9.6.4.40 (fixed in 9.6.4.40); from 9.8, before 9.8.4.20 (fixed in 9.8.4.20); from 9.9, before 9.9.2.66 (fixed in 9.9.2.66); from 9.10, before 9.10.1.37 (fixed in 9.10.1.37); from 9.12, before 9.12.3.2 (fixed in 9.12.3.2); from 9.13, before 9.13.1.7 (fixed in 9.13.1.7)
Cisco ASA 5505 Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5510 Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5512-X Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5515-X Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5520 Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5525-X Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5540 Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5545-X Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5550 Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5555-X Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5580 Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco ASA 5585-X Firmware: version 9.4(4) only; version 9.8(4.18) only; version 100.13(0) only
Cisco Secure Firewall Threat Defense: from 6.2.3, before 6.2.3.16 (fixed in 6.2.3.16); from 6.3.0, before 6.3.0.6 (fixed in 6.3.0.6); 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.