CVE-2018-0251 Cross-site scripting in Cisco Adaptive Security Appliance
An unauthenticated remote attacker can execute arbitrary script code or access sensitive browser-based information via a crafted link in the Cisco ASA SSL VPN portal.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2018-0251?
CVE-2018-0251 is a medium-severity cross-site scripting vulnerability in Cisco Adaptive Security Appliance Software, published on 19 Apr 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
A vulnerability in the Web Server Authentication Required screen of the Clientless Secure Sockets Layer (SSL) VPN portal of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of that portal on an affected device. The vulnerability is due to insufficient validation of user-supplied input by the web-based interface of an affected device. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the portal or allow the attacker to access sensitive browser-based information. This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco ASA Software: 3000 Series Industrial Security Appliances, Adaptive Security Virtual Appliance (ASAv), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches, ASA Services Module for Cisco 7600 Series Routers. Cisco Bug IDs: CSCvh20742.
Weakness: CWE-79
Which versions are affected by CVE-2018-0251?
It affects 1 product.
Products include Cisco Adaptive Security Appliance Software.
How do I fix CVE-2018-0251?
No fix has been published for CVE-2018-0251 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2018-0251 being exploited?
There is no known exploitation of CVE-2018-0251 in the wild and no public exploit code.
Other vulnerabilities in Cisco Adaptive Security Appliance Software
- CVE-2025-20333 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow
- CVE-2016-6366 Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow
- CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection
- CVE-2024-20353 Cisco ASA and FTD Denial of Service
- CVE-2016-6367 Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution
All Cisco Adaptive Security Appliance Software vulnerabilities
Sources
Also known as GHSA-59wx-wx8g-cfcx.