CVE-2020-3529: Cisco Adaptive Security Appliance

High severity, CVSS 7.5. EPSS: 1.9% chance of exploitation in the next 30 days.

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 the attacker to exhaust DMA memory on the device and cause a DoS condition.

Affected products

• Cisco Adaptive Security Appliance: before 9.6.4.45 (fixed in 9.6.4.45)
• Cisco Adaptive Security Appliance Software: from 9.8.0, before 9.8.4.29 (fixed in 9.8.4.29); from 9.9.0, before 9.9.2.80 (fixed in 9.9.2.80); from 9.10.0, before 9.10.1.44 (fixed in 9.10.1.44); from 9.12.0, before 9.12.4.4 (fixed in 9.12.4.4); from 9.13.0, before 9.13.1.13 (fixed in 9.13.1.13); from 9.14.0, before 9.14.1.30 (fixed in 9.14.1.30)
• Cisco Secure Firewall Threat Defense: before 6.3.0.6 (fixed in 6.3.0.6); from 6.4.0, before 6.4.0.10 (fixed in 6.4.0.10); from 6.5.0, before 6.5.0.5 (fixed in 6.5.0.5); from 6.6.0, before 6.6.1 (fixed in 6.6.1)

Published 2020-10-21. Last modified 2026-08-11.