---
id: CVE-2018-15398
title: >-
  A vulnerability in the per-user-override feature of Cisco Adaptive Security
  Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software
  could allow an unauthenticated, remote attacker to bypass an access control
  list (ACL)…
summary: >-
  A vulnerability in the per-user-override feature of Cisco Adaptive Security
  Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software
  could allow an unauthenticated, remote attacker to bypass an access control
  list (ACL)…
severity: medium
cvss: 4
cvssVector: 'CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N'
cwe:
  - CWE-284
vendor: cisco
product: adaptive_security_appliance_software
affected:
  - adaptive_security_appliance_software = 9.6(4.3)
  - adaptive_security_appliance_software = 9.4(2)
  - adaptive_security_appliance_software = 9.4(4)
  - secure_firewall_threat_defense = 6.2.0
published: '2018-10-05'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2018-15398'
references:
  - url: 'http://www.securityfocus.com/bid/105517'
    label: psirt@cisco.com
  - url: 'http://www.securitytracker.com/id/1041788'
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181003-asa-acl-bypass
    label: psirt@cisco.com
  - url: 'http://www.securityfocus.com/bid/105517'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://www.securitytracker.com/id/1041788'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181003-asa-acl-bypass
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01885
epssPercentile: 0.7858
ingestedAt: '2026-08-11T19:48:25.910Z'
---

## Overview

A vulnerability in the per-user-override feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass an access control list (ACL) that is configured for an interface of an affected device. The vulnerability is due to errors that could occur when the affected software constructs and applies per-user-override rules. An attacker could exploit this vulnerability by connecting to a network through an affected device that has a vulnerable configuration. A successful exploit could allow the attacker to access resources that are behind the affected device and would typically be protected by the interface ACL.

## Affected

- `adaptive_security_appliance_software = 9.6(4.3)`
- `adaptive_security_appliance_software = 9.4(2)`
- `adaptive_security_appliance_software = 9.4(4)`
- `secure_firewall_threat_defense = 6.2.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.