CVE-2018-0101
CriticalExploitedPublic exploitA 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.
Published Jan 29, 2018 · Updated Aug 11, 2026
Key Facts
Patch immediately- CVE-2018-0101 is a critical-severity vulnerability (CVSS 10.0 v3) affecting Adaptive Security Appliance Software (Cisco), Firepower Threat Defense (Cisco), Secure Firewall Threat Defense (Cisco) and 1 more product.
- It is exploited in the wild, listed in Industry KEV feed since Jan 29, 2018. Public exploit code is available.
- EPSS estimates a 87% probability of exploitation in the next 30 days.
- Fixed versions are available, including Adaptive Security Appliance Software 9.1.7.23, Adaptive Security Appliance Software 9.2.4.27, Adaptive Security Appliance Software 9.4.4.16.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3
10.0
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
87%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
1 catalog listing
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2018-0101 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Jan 29, 2018 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
15 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Adaptive Security Appliance SoftwareCisco | See advisory | 9.1.7.23 |
| Firepower Threat DefenseCisco | 6.0.0, 6.0.1, 6.1.0, 6.2.0, 6.2.1, 6.2.2 | n/a |
| Secure Firewall Threat DefenseCisco | 6.0.0, 6.0.1, 6.1.0, 6.2.0, 6.2.1, 6.2.2 | n/a |
| Cisco Adaptive Security Appliance | >= Cisco Adaptive Security Appliance | n/a |
Patched Releases
Adaptive Security Appliance Software
9.1.7.23, 9.2.4.27, 9.4.4.16, 9.6.4.3, 9.7.1.21, 9.8.2.20, 9.9.1.2
Timeline
Publicly disclosed
Jan 29, 2018
Added to Industry KEV feed
Jan 29, 2018
Last updated
Aug 11, 2026
Weakness Type
- CWE-415 Double Free
References
- advisoryhttps://icanthackit.wordpress.com/2018/01/30/thoughts-on-the-handling-cve-2018-0101-cisco-bug-cscvg35618/
- advisoryhttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180129-asa1
- advisory102845
- advisory1040292
- exploithttps://pastebin.com/YrBcG2Ln
FAQ
Common Questions.
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.
Affected: Adaptive Security Appliance Software (Cisco); Firepower Threat Defense (Cisco) versions 6.0.0, 6.0.1, 6.1.0, 6.2.0, 6.2.1, 6.2.2; Secure Firewall Threat Defense (Cisco) versions 6.0.0, 6.0.1, 6.1.0, 6.2.0, 6.2.1, 6.2.2, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Jan 29, 2018.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Adaptive Security Appliance Software 9.1.7.23, Adaptive Security Appliance Software 9.2.4.27, Adaptive Security Appliance Software 9.4.4.16.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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