---
id: CVE-2018-15388
title: >-
  A vulnerability in the WebVPN login process of Cisco Adaptive Security
  Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software
  could allow an unauthenticated, remote attacker to cause increased CPU
  utilization on an af…
summary: >-
  A vulnerability in the WebVPN login process of Cisco Adaptive Security
  Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software
  could allow an unauthenticated, remote attacker to cause increased CPU
  utilization on an af…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-400
vendor: cisco
product: adaptive_security_appliance_software
affected:
  - adaptive_security_appliance_software < 9.4.4.34
  - 'adaptive_security_appliance_software >= 9.5, < 9.6.4.25'
  - 'adaptive_security_appliance_software >= 9.7, < 9.8.4'
  - 'adaptive_security_appliance_software >= 9.9, < 9.9.2.50'
  - secure_firewall_threat_defense < 6.2.3.12
patched:
  - adaptive_security_appliance_software 9.9.2.50
  - secure_firewall_threat_defense 6.2.3.12
published: '2019-05-03'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2018-15388'
references:
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-sd-cpu-dos
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-sd-cpu-dos
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01967
epssPercentile: 0.79498
ingestedAt: '2026-08-11T19:48:26.077Z'
---

## Overview

A vulnerability in the WebVPN login process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause increased CPU utilization on an affected device. The vulnerability is due to excessive processing load for existing WebVPN login operations. An attacker could exploit this vulnerability by sending multiple WebVPN login requests to the device. A successful exploit could allow the attacker to increase CPU load on the device, resulting in a denial of service (DoS) condition.

## Affected

- `adaptive_security_appliance_software < 9.4.4.34`
- `adaptive_security_appliance_software >= 9.5, < 9.6.4.25`
- `adaptive_security_appliance_software >= 9.7, < 9.8.4`
- `adaptive_security_appliance_software >= 9.9, < 9.9.2.50`
- `secure_firewall_threat_defense < 6.2.3.12`

## Remediation

Upgrade past the affected range:

- `adaptive_security_appliance_software 9.9.2.50`
- `secure_firewall_threat_defense 6.2.3.12`