---
id: CVE-2020-3303
title: >-
  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 denia…
summary: >-
  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 denia…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-399
  - CWE-400
vendor: cisco
product: adaptive_security_appliance
affected:
  - adaptive_security_appliance < 9.6.4.36
  - 'adaptive_security_appliance_software >= 9.7, < 9.8.4.10'
  - 'adaptive_security_appliance_software >= 9.9, < 9.10.1.30'
  - 'adaptive_security_appliance_software >= 9.12, < 9.12.2.9'
  - secure_firewall_threat_defense < 6.3.0.5
  - 'secure_firewall_threat_defense >= 6.4.0, < 6.4.0.6'
patched:
  - adaptive_security_appliance 9.6.4.36
  - adaptive_security_appliance_software 9.12.2.9
  - secure_firewall_threat_defense 6.4.0.6
published: '2020-05-06'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-3303'
references:
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-dos-BqYFRJt9
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-dos-BqYFRJt9
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01233
epssPercentile: 0.672
ingestedAt: '2026-08-11T19:48:27.880Z'
---

## Overview

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

- `adaptive_security_appliance < 9.6.4.36`
- `adaptive_security_appliance_software >= 9.7, < 9.8.4.10`
- `adaptive_security_appliance_software >= 9.9, < 9.10.1.30`
- `adaptive_security_appliance_software >= 9.12, < 9.12.2.9`
- `secure_firewall_threat_defense < 6.3.0.5`
- `secure_firewall_threat_defense >= 6.4.0, < 6.4.0.6`

## Remediation

Upgrade past the affected range:

- `adaptive_security_appliance 9.6.4.36`
- `adaptive_security_appliance_software 9.12.2.9`
- `secure_firewall_threat_defense 6.4.0.6`