Applied Cybernetics Group
Threat intel → detection pipeline
Friday, September 18, 2026
Data as of 13:09 UTC

known ransomware use

Cisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability

Added to KEV
2021-11-03
Federal due date
2022-05-03
Vendor
Cisco
Product
Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)
EPSS
99.7th percentile (score 0.856, as of 2026-09-16)
NVD CVSS v3.1
6.1 (MEDIUM)
Ransomware use
Known
ATT&CK
T1059 , T1204.001 , T1217 · signal rollup
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2020-3580

CISA short description

Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain an insufficient input validation vulnerability for user-supplied input by the web services interface. Successful exploitation could allow an attacker to perform cross-site scripting (XSS) in the context of the interface or access sensitive browser-based information.

Required action

Apply updates per vendor instructions.

NVD 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.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.