---
id: "CVE-2020-3580"
kind: "vulnerability"
aliases: ["CVE-2020-3580"]
title: "Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD): Cisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability"
severity: "high"
cvss: 6.1
epss: 0.85575
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["asa", "cisco", "exploited", "firepower-threat-defense", "infrastructure", "network-appliance", "ransomware"]
not_affected_if: ["web-services-disabled"]
published_at: "2020-10-21T19:15:18+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-3580", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2020-3580", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-3580", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD): Cisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability

Cisco ASA and Firepower Threat Defense web services interface does not validate user input, allowing cross-site scripting. An attacker can run script in an administrator's browser session on the interface or read sensitive browser-based information.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) affected ? fixed ?

## Fix

Apply the Cisco updates per vendor instructions; the specific fixed versions are not stated in the sources.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-3580
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2020-3580
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2020-3580

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_