CVE-2020-3580: Cisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability

Vulnerability summary

CVE-2020-3580 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). It is known to be exploited: CISA lists it, first on 03-11-2021. It has been used in ransomware campaigns. EPSS estimates a 85.58% chance of exploitation in the next 30 days, higher than 99.7% of scored vulnerabilities.

Timeline

1. 21-10-2020
   PublishedVulnerability first disclosed.
2. 03-11-2021
   Added to CISA KEVCisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability
3. 03-05-2022
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

Multiple vulnerabilities in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct cross-site scripting (XSS) attacks against a user of the web services interface of an affected device. The vulnerabilities are due to insufficient validation of user-supplied input by the web services interface of an affected device. An attacker could exploit these vulnerabilities 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 interface or allow the attacker to access sensitive, browser-based information. Note: These vulnerabilities affect only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.