CVE-2020-3580
Published: November 3, 2021
Official 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.
CISA KEV Advisory
Cisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability
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.
Apply updates per vendor instructions.
Risk Analysis
This vulnerability in Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) allows for cross-site scripting (XSS) due to insufficient input validation in the web services interface. Successful exploitation could allow an attacker to access sensitive browser-based information or perform actions in the context of the interface. Its high EPSS score of 0.92623 and inclusion in CISA's KEV indicate a high likelihood of exploitation.
This vulnerability is actively exploited in the wild and is listed in CISA's KEV, confirming its active use by threat actors. The web services interface makes it remotely exploitable.
Apply the latest security updates from Cisco to ASA and FTD to address the input validation vulnerability. Implement strong content security policies and input sanitization on web interfaces.
Technical Analysis
CVE-2020-3580 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2020-3580 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (1)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2020-3580 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1