CVE-2020-3580 Cisco ASA and FTD Cross-Site Scripting (XSS)
Unauthenticated remote attackers can execute arbitrary script code or access sensitive browser-based information via crafted links in Cisco ASA/FTD web interfaces.
- Exploited in the wild
- Since 3 Nov 2021
- 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-2020-3580?
CVE-2020-3580 is a medium-severity cross-site scripting vulnerability in Cisco Adaptive Security Appliance Software, published on 21 Oct 2020. 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
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.
Weakness: CWE-79
Which versions are affected by CVE-2020-3580?
It affects 2 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2020-3580?
No fix has been published for CVE-2020-3580 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 3 May 2022.
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-2020-3580 being exploited?
Yes. Attackers have exploited CVE-2020-3580 in the wild since at least 3 Nov 2021, including in ransomware campaigns.
Public exploit code: 1 Nuclei template and 4 proofs of concept on GitHub.
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-rr9h-g433-576p.