10.0Critical

Cisco Adaptive Security Appliance Software

CVE-2018-0101

A vulnerability in the Secure Sockets Layer (SSL) VPN functionality of the Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause a reload of the affected system or to remotely execute code. The vulnerability is due to an attempt to double free a region of memory when the webvpn feature is enabled on the Cisco ASA device. An attacker could exploit this vulnerability by sending multiple, crafted XML packets to a webvpn-configured interface on the affected system. An exploit could allow the attacker to execute arbitrary code and obtain full control of the system, or cause a reload of the affected device. This vulnerability affects Cisco ASA Software that is running on the following Cisco products: 3000 Series Industrial Security Appliance (ISA), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, ASA 1000V Cloud Firewall, Adaptive Security Virtual Appliance (ASAv), Firepower 2100 Series Security Appliance, Firepower 4110 Security Appliance, Firepower 9300 ASA Security Module, Firepower Threat Defense Software (FTD). Cisco Bug IDs: CSCvg35618.

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.
  • Code showing how to exploit it has been published, but real attacks have not been confirmed.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 87% chance of attack attempts being seen in the next 30 days, ranking above 99% of all known flaws.

What to do

  1. 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.
  2. 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.

Scoring

CVSS
10.0 (v3.0)
Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Weakness
CWE-415
Assigned by
psirt@cisco.com

Dates

Published
2018-01-29
Last modified
2026-08-11
Sources
NVD

Affected products

  • Cisco Adaptive Security Appliance Software- 9.1.7.23, 9.2.0 - 9.2.4.27, 9.3.0 - 9.4.4.16, 9.5.0 - 9.6.4.3, 9.7.0 - 9.7.1.21, 9.8.0 - 9.8.2.20, 9.9.0 - 9.9.1.2
  • Cisco Secure Firewall Threat Defense6.0.0, 6.0.1, 6.1.0, 6.2.0, 6.2.1, 6.2.2

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

References