---
id: CVE-2018-15454
title: >-
  A vulnerability in the Session Initiation Protocol (SIP) inspection engine of
  Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat
  Defense (FTD) Software could allow an unauthenticated, remote attacker to
  cause an …
summary: >-
  A vulnerability in the Session Initiation Protocol (SIP) inspection engine of
  Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat
  Defense (FTD) Software could allow an unauthenticated, remote attacker to
  cause an …
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-20
  - CWE-20
vendor: cisco
product: secure_firewall_threat_defense
affected:
  - 'adaptive_security_appliance_software >= 9.4, < 9.4.4.27'
  - 'adaptive_security_appliance_software >= 9.6, < 9.6.4.18'
  - 'adaptive_security_appliance_software >= 9.8, < 9.8.3.16'
  - 'adaptive_security_appliance_software >= 9.9, < 9.9.2.32'
  - 'adaptive_security_appliance_software >= 9.10, < 9.10.1.2'
  - 'secure_firewall_threat_defense >= 6.1.0, < 6.1.0.7'
  - 'secure_firewall_threat_defense >= 6.2.0, < 6.2.0.6'
  - 'secure_firewall_threat_defense >= 6.2.2, < 6.2.2.4'
  - 'secure_firewall_threat_defense >= 6.2.3, < 6.2.3.7'
patched:
  - adaptive_security_appliance_software 9.10.1.2
  - secure_firewall_threat_defense 6.2.3.7
published: '2018-11-01'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2018-15454'
references:
  - url: 'http://www.securityfocus.com/bid/105768'
    label: psirt@cisco.com
  - url: 'http://www.securitytracker.com/id/1042129'
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181031-asaftd-sip-dos
    label: psirt@cisco.com
  - url: 'http://www.securityfocus.com/bid/105768'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://www.securitytracker.com/id/1042129'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181031-asaftd-sip-dos
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - in-the-wild
epss: 0.04381
epssPercentile: 0.90867
exploited: true
zeroDay: true
ingestedAt: '2026-08-11T19:48:25.976Z'
---

## Overview

A vulnerability in the Session Initiation Protocol (SIP) inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload or trigger high CPU, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of SIP traffic. An attacker could exploit this vulnerability by sending SIP requests designed to specifically trigger this issue at a high rate across an affected device. Software updates that address this vulnerability are not yet available.

## Affected

- `adaptive_security_appliance_software >= 9.4, < 9.4.4.27`
- `adaptive_security_appliance_software >= 9.6, < 9.6.4.18`
- `adaptive_security_appliance_software >= 9.8, < 9.8.3.16`
- `adaptive_security_appliance_software >= 9.9, < 9.9.2.32`
- `adaptive_security_appliance_software >= 9.10, < 9.10.1.2`
- `secure_firewall_threat_defense >= 6.1.0, < 6.1.0.7`
- `secure_firewall_threat_defense >= 6.2.0, < 6.2.0.6`
- `secure_firewall_threat_defense >= 6.2.2, < 6.2.2.4`
- `secure_firewall_threat_defense >= 6.2.3, < 6.2.3.7`

## Remediation

Upgrade past the affected range:

- `adaptive_security_appliance_software 9.10.1.2`
- `secure_firewall_threat_defense 6.2.3.7`