---
id: CVE-2020-3334
title: >-
  A vulnerability in the ARP packet processing of Cisco Adaptive Security
  Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for
  Cisco Firepower 2100 Series Security Appliances could allow an
  unauthenticated, adjace…
summary: >-
  A vulnerability in the ARP packet processing of Cisco Adaptive Security
  Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for
  Cisco Firepower 2100 Series Security Appliances could allow an
  unauthenticated, adjace…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'
cwe:
  - CWE-399
  - CWE-400
vendor: cisco
product: secure_firewall_threat_defense
affected:
  - 'adaptive_security_appliance_software >= 9.10, < 9.10.1.37'
  - 'adaptive_security_appliance_software >= 9.12, < 9.12.3'
  - 'adaptive_security_appliance_software >= 9.13, < 9.13.1.2'
  - secure_firewall_threat_defense < 6.6.0
patched:
  - adaptive_security_appliance_software 9.13.1.2
  - secure_firewall_threat_defense 6.6.0
published: '2020-05-06'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-3334'
references:
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fp2100-arp-dos-kLdCK8ks
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fp2100-arp-dos-kLdCK8ks
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00433
epssPercentile: 0.37097
ingestedAt: '2026-08-11T19:48:28.246Z'
---

## Overview

A vulnerability in the ARP packet processing of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series Security Appliances could allow an unauthenticated, adjacent attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition on an affected device. The vulnerability is due to incorrect processing of ARP packets received by the management interface of an affected device. An attacker could exploit this vulnerability by sending a series of unicast ARP packets in a short timeframe that would reach the management interface of an affected device. A successful exploit could allow the attacker to consume resources on an affected device, which would prevent the device from sending internal system keepalives and eventually cause the device to reload, resulting in a denial of service (DoS) condition.

## Affected

- `adaptive_security_appliance_software >= 9.10, < 9.10.1.37`
- `adaptive_security_appliance_software >= 9.12, < 9.12.3`
- `adaptive_security_appliance_software >= 9.13, < 9.13.1.2`
- `secure_firewall_threat_defense < 6.6.0`

## Remediation

Upgrade past the affected range:

- `adaptive_security_appliance_software 9.13.1.2`
- `secure_firewall_threat_defense 6.6.0`