---
id: CVE-2020-3196
title: >-
  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
  attacke…
summary: >-
  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
  attacke…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-400
vendor: cisco
product: secure_firewall_threat_defense
affected:
  - 'secure_firewall_threat_defense >= 6.2.3, < 6.2.3.16'
  - 'secure_firewall_threat_defense >= 6.3.0, < 6.3.0.6'
  - 'secure_firewall_threat_defense >= 6.4.0, < 6.4.0.9'
  - 'secure_firewall_threat_defense >= 6.5.0, < 6.5.0.5'
  - asa_5505_firmware = 9.4(4)
  - asa_5505_firmware = 9.8(4.18)
  - asa_5505_firmware = 100.13(0)
  - asa_5510_firmware = 9.4(4)
  - asa_5510_firmware = 9.8(4.18)
  - asa_5510_firmware = 100.13(0)
  - asa_5512-x_firmware = 9.4(4)
  - asa_5512-x_firmware = 9.8(4.18)
  - asa_5512-x_firmware = 100.13(0)
  - asa_5515-x_firmware = 9.4(4)
  - asa_5515-x_firmware = 9.8(4.18)
  - asa_5515-x_firmware = 100.13(0)
  - asa_5520_firmware = 9.4(4)
  - asa_5520_firmware = 9.8(4.18)
  - asa_5520_firmware = 100.13(0)
  - asa_5525-x_firmware = 9.4(4)
  - asa_5525-x_firmware = 9.8(4.18)
  - asa_5525-x_firmware = 100.13(0)
  - asa_5540_firmware = 9.4(4)
  - asa_5540_firmware = 9.8(4.18)
  - asa_5540_firmware = 100.13(0)
  - asa_5545-x_firmware = 9.4(4)
  - asa_5545-x_firmware = 9.8(4.18)
  - asa_5545-x_firmware = 100.13(0)
  - asa_5550_firmware = 9.4(4)
  - asa_5550_firmware = 9.8(4.18)
  - asa_5550_firmware = 100.13(0)
  - asa_5555-x_firmware = 9.4(4)
  - asa_5555-x_firmware = 9.8(4.18)
  - asa_5555-x_firmware = 100.13(0)
  - asa_5580_firmware = 9.4(4)
  - asa_5580_firmware = 9.8(4.18)
  - asa_5580_firmware = 100.13(0)
  - asa_5585-x_firmware = 9.4(4)
  - asa_5585-x_firmware = 9.8(4.18)
  - asa_5585-x_firmware = 100.13(0)
  - 'adaptive_security_appliance_software >= 9.6, < 9.6.4.40'
  - 'adaptive_security_appliance_software >= 9.8, < 9.8.4.20'
  - 'adaptive_security_appliance_software >= 9.9, < 9.9.2.66'
  - 'adaptive_security_appliance_software >= 9.10, < 9.10.1.37'
  - 'adaptive_security_appliance_software >= 9.12, < 9.12.3.2'
  - 'adaptive_security_appliance_software >= 9.13, < 9.13.1.7'
patched:
  - secure_firewall_threat_defense 6.5.0.5
  - adaptive_security_appliance_software 9.13.1.7
published: '2020-05-06'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-3196'
references:
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-vpn-dos-qY7BHpjN
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-vpn-dos-qY7BHpjN
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.0192
epssPercentile: 0.79026
ingestedAt: '2026-08-11T19:48:27.614Z'
---

## Overview

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

- `secure_firewall_threat_defense >= 6.2.3, < 6.2.3.16`
- `secure_firewall_threat_defense >= 6.3.0, < 6.3.0.6`
- `secure_firewall_threat_defense >= 6.4.0, < 6.4.0.9`
- `secure_firewall_threat_defense >= 6.5.0, < 6.5.0.5`
- `asa_5505_firmware = 9.4(4)`
- `asa_5505_firmware = 9.8(4.18)`
- `asa_5505_firmware = 100.13(0)`
- `asa_5510_firmware = 9.4(4)`
- `asa_5510_firmware = 9.8(4.18)`
- `asa_5510_firmware = 100.13(0)`
- `asa_5512-x_firmware = 9.4(4)`
- `asa_5512-x_firmware = 9.8(4.18)`
- `asa_5512-x_firmware = 100.13(0)`
- `asa_5515-x_firmware = 9.4(4)`
- `asa_5515-x_firmware = 9.8(4.18)`
- `asa_5515-x_firmware = 100.13(0)`
- `asa_5520_firmware = 9.4(4)`
- `asa_5520_firmware = 9.8(4.18)`
- `asa_5520_firmware = 100.13(0)`
- `asa_5525-x_firmware = 9.4(4)`
- `asa_5525-x_firmware = 9.8(4.18)`
- `asa_5525-x_firmware = 100.13(0)`
- `asa_5540_firmware = 9.4(4)`
- `asa_5540_firmware = 9.8(4.18)`
- `asa_5540_firmware = 100.13(0)`
- `asa_5545-x_firmware = 9.4(4)`
- `asa_5545-x_firmware = 9.8(4.18)`
- `asa_5545-x_firmware = 100.13(0)`
- `asa_5550_firmware = 9.4(4)`
- `asa_5550_firmware = 9.8(4.18)`
- `asa_5550_firmware = 100.13(0)`
- `asa_5555-x_firmware = 9.4(4)`
- `asa_5555-x_firmware = 9.8(4.18)`
- `asa_5555-x_firmware = 100.13(0)`
- `asa_5580_firmware = 9.4(4)`
- `asa_5580_firmware = 9.8(4.18)`
- `asa_5580_firmware = 100.13(0)`
- `asa_5585-x_firmware = 9.4(4)`
- `asa_5585-x_firmware = 9.8(4.18)`
- `asa_5585-x_firmware = 100.13(0)`
- `adaptive_security_appliance_software >= 9.6, < 9.6.4.40`
- `adaptive_security_appliance_software >= 9.8, < 9.8.4.20`
- `adaptive_security_appliance_software >= 9.9, < 9.9.2.66`
- `adaptive_security_appliance_software >= 9.10, < 9.10.1.37`
- `adaptive_security_appliance_software >= 9.12, < 9.12.3.2`
- `adaptive_security_appliance_software >= 9.13, < 9.13.1.7`

## Remediation

Upgrade past the affected range:

- `secure_firewall_threat_defense 6.5.0.5`
- `adaptive_security_appliance_software 9.13.1.7`