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.
- Vendor
- Cisco
- Product
- Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)
- CVSS
- 6.1
- EPSS (exploit probability)
- 85.6%
- Status
- kevransomware use
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2020-3580 being exploited?
Yes. CISA added CVE-2020-3580 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild. CISA marks it as known to be used in ransomware campaigns.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 85.6% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2020-3580 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply updates per vendor instructions.
US federal civilian agencies must remediate by (181 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2026-20349 Cisco ASA and FTD VPN Heap Inspection Denial-of-Service Flawwrite-up | [ HIGH ] | 8.6 | 1.0% | |
| CVE-2025-20362 Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Missing Authorization Vulnerability | [ MEDIUM ] | 6.5 | 86.7% | |
| CVE-2025-20333 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability | [ CRITICAL ] | 9.9 | 72.0% | |
| CVE-2024-20481 Cisco ASA and FTD Denial-of-Service Vulnerability | [ MEDIUM ] | 5.8 | 15.9% | |
| CVE-2024-20359 Cisco ASA and FTD Privilege Escalation Vulnerability | [ MEDIUM ] | 6.0 | 18.8% | |
| CVE-2024-20353 Cisco ASA and FTD Denial of Service Vulnerability | [ HIGH ] | 8.6 | 69.8% | |
| CVE-2020-3259 Cisco ASA and FTD Information Disclosure Vulnerabilityransomware use | [ HIGH ] | 7.5 | 71.5% | |
| CVE-2023-20269 Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerabilityransomware use | [ MEDIUM ] | 5.0 | 26.6% |