Vulnerability · CVE-2020-3529
Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Uncontrolled Resource Consumption
Published Apr 23, 2025 · corrected/updated Apr 23, 2025 · Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) · evidence confidence very high
A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to inefficient direct memory access (DMA) memory management during the negotiation phase of an SSL VPN connection. An attacker could exploit this vulnerability by sending a steady stream of crafted Datagram TLS (DTLS) traffic to an affected device. A successful exploit could allow
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2020-3529 is a unknown public vulnerability record for Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). CISA lists it as known exploited. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: no CVSS/EPSS yet. CISA lists it as known exploited. Sources contributing to this record: vulncheck_kev. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Confirmed in CISA KEV since Apr 23, 2025. Listed in CISA KEV and VulnCheck KEV.
Patch and remediation
Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Technology hubs
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Apr 23, 2025 · VulnCheck KEV
Detected
A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to inefficient direct memory access (DMA) memory management during the negotiation
Apr 23, 2025 · CISA KEV
Known exploited
Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected
- vendor Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)version unspecified
Sources
- VulnCheck KEVConfirmed exploitationCVE-2020-3529
A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a reload of an affected device, resulting in a denial of service (DoS
vulncheck.com