---
id: CVE-2019-15256
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
  trigger a rel…
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
  trigger a rel…
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-399
  - CWE-400
vendor: cisco
product: adaptive_security_appliance_software
affected:
  - 'adaptive_security_appliance_software >= 9.7, < 9.8.4.10'
  - 'adaptive_security_appliance_software >= 9.9, < 9.9.2.47'
  - 'adaptive_security_appliance_software >= 9.10, < 9.10.1.30'
  - 'adaptive_security_appliance_software >= 9.12, < 9.12.2.5'
  - 'secure_firewall_threat_defense >= 6.2.0, < 6.2.3.11'
  - 'secure_firewall_threat_defense >= 6.3.0, < 6.3.0.2'
  - asa_5505_firmware = 9.9(2.4)
  - asa_5505_firmware = 201.4(1.21)
  - asa_5510_firmware = 9.9(2.4)
  - asa_5510_firmware = 201.4(1.21)
  - asa_5512-x_firmware = 9.9(2.4)
  - asa_5512-x_firmware = 201.4(1.21)
  - asa_5515-x_firmware = 9.9(2.4)
  - asa_5515-x_firmware = 201.4(1.21)
  - asa_5520_firmware = 9.9(2.4)
  - asa_5520_firmware = 201.4(1.21)
  - asa_5525-x_firmware = 9.9(2.4)
  - asa_5525-x_firmware = 201.4(1.21)
  - asa_5540_firmware = 9.9(2.4)
  - asa_5540_firmware = 201.4(1.21)
  - asa_5545-x_firmware = 9.9(2.4)
  - asa_5545-x_firmware = 201.4(1.21)
  - asa_5550_firmware = 9.9(2.4)
  - asa_5550_firmware = 201.4(1.21)
  - asa_5555-x_firmware = 9.9(2.4)
  - asa_5555-x_firmware = 201.4(1.21)
  - asa_5580_firmware = 9.9(2.4)
  - asa_5580_firmware = 201.4(1.21)
patched:
  - adaptive_security_appliance_software 9.12.2.5
  - secure_firewall_threat_defense 6.3.0.2
published: '2019-10-02'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2019-15256'
references:
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191002-asa-ftd-ikev1-dos
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191002-asa-ftd-ikev1-dos
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01967
epssPercentile: 0.79522
ingestedAt: '2026-08-11T19:48:27.143Z'
---

## 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 trigger a reload of an affected device, resulting in 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. The attacker does not need valid credentials to authenticate the VPN session, nor does the attacker's source address need to match a peer statement in the crypto map applied to the ingress interface of the affected device. An exploit could allow the attacker to exhaust system memory resources, leading to a reload of an affected device.

## Affected

- `adaptive_security_appliance_software >= 9.7, < 9.8.4.10`
- `adaptive_security_appliance_software >= 9.9, < 9.9.2.47`
- `adaptive_security_appliance_software >= 9.10, < 9.10.1.30`
- `adaptive_security_appliance_software >= 9.12, < 9.12.2.5`
- `secure_firewall_threat_defense >= 6.2.0, < 6.2.3.11`
- `secure_firewall_threat_defense >= 6.3.0, < 6.3.0.2`
- `asa_5505_firmware = 9.9(2.4)`
- `asa_5505_firmware = 201.4(1.21)`
- `asa_5510_firmware = 9.9(2.4)`
- `asa_5510_firmware = 201.4(1.21)`
- `asa_5512-x_firmware = 9.9(2.4)`
- `asa_5512-x_firmware = 201.4(1.21)`
- `asa_5515-x_firmware = 9.9(2.4)`
- `asa_5515-x_firmware = 201.4(1.21)`
- `asa_5520_firmware = 9.9(2.4)`
- `asa_5520_firmware = 201.4(1.21)`
- `asa_5525-x_firmware = 9.9(2.4)`
- `asa_5525-x_firmware = 201.4(1.21)`
- `asa_5540_firmware = 9.9(2.4)`
- `asa_5540_firmware = 201.4(1.21)`
- `asa_5545-x_firmware = 9.9(2.4)`
- `asa_5545-x_firmware = 201.4(1.21)`
- `asa_5550_firmware = 9.9(2.4)`
- `asa_5550_firmware = 201.4(1.21)`
- `asa_5555-x_firmware = 9.9(2.4)`
- `asa_5555-x_firmware = 201.4(1.21)`
- `asa_5580_firmware = 9.9(2.4)`
- `asa_5580_firmware = 201.4(1.21)`

## Remediation

Upgrade past the affected range:

- `adaptive_security_appliance_software 9.12.2.5`
- `secure_firewall_threat_defense 6.3.0.2`