A vulnerability in the SSL/TLS session handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory leak when closing SSL/TLS connections in a specific state. An attacker could exploit this vulnerability by establishing several SSL/TLS sessions and ensuring they are closed under certain conditions. A successful exploit could allow the attacker to exhaust memory resources in the affected device, which would prevent it from processing new SSL/TLS connections, resulting in a DoS. Manual intervention is required to recover an affected device.
Conclusion & alert: CVE-2020-3572 is rated Moderate Risk (63.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.86%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-11-21 | 1.31% | 1.86% | +0.55% |
| 2 | 2025-11-18 | 1.86% | 1.31% | -0.55% |
| 3 | 2025-03-30 | — | 1.86% | — |
Full EPSS history (11 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 8.6 | 3.1 | HIGH |
|
3.9 | 4.0 | [email protected] |
| 8.6 | 3.1 | HIGH |
|
3.9 | 4.0 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| cisco | adaptive_security_appliance | < 9.6 | cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* |
| cisco | firepower_threat_defense | < 6.3.0.6 | cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* |
| cisco | firepower_threat_defense | >= 6.4.0, < 6.4.0.10 | cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* |
| cisco | firepower_threat_defense | >= 6.5.0, < 6.6.1 | cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | >= 9.8.0, < 9.8.4.26 | cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | >= 9.9.0, < 9.9.2.80 | cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | >= 9.10.0, < 9.10.1.44 | cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | >= 9.12.0, < 9.12.4.4 | cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | >= 9.13.0, < 9.13.1.13 | cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | >= 9.14.0, < 9.14.1.19 | cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* |