CVE-2018-15398

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.

What this means for your business

It affects Cisco Adaptive Security Appliance Software. It matters if your company, or a supplier that handles your data, runs it.
An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.

What to do

1Check whether your company or your suppliers run Cisco Adaptive Security Appliance Software, and which version. The affected versions are listed further down this page.
2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposed Book a call

Scoring

CVSS: 4.0 (v3.0)
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Weakness: CWE-284
Assigned by: psirt@cisco.com

Dates

Published: 2018-10-05
Last modified: 2026-08-11
Sources: NVD

Affected products

Cisco Adaptive Security Appliance Software9.6\(4.3\), 9.4\(2\), 9.4\(4\)
Cisco Secure Firewall Threat Defense6.2.0

As listed in the NVD configuration data. Not a statement about your estate.