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
99.8th percentile (score 0.933, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Known
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.

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.