CVE-2023-20095: Cisco Adaptive Security Appliance Software

High severity, CVSS 8.6. EPSS: 0.6% chance of exploitation in the next 30 days.

A vulnerability in the remote access VPN feature 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. This vulnerability is due to improper handling of HTTPS requests. An attacker could exploit this vulnerability by sending crafted HTTPS requests to an affected system. A successful exploit could allow the attacker to cause resource exhaustion, resulting in a DoS condition.

Affected products

• Cisco Adaptive Security Appliance Software: version 9.8.1 only; version 9.8.1.5 only; version 9.8.1.7 only; version 9.8.2 only; version 9.8.2.8 only; version 9.8.2.14 only; …
• Cisco Secure Firewall Threat Defense: version 6.2.3 only; version 6.2.3.0 only; version 6.2.3.1 only; version 6.2.3.2 only; version 6.2.3.3 only; version 6.2.3.4 only; …

Published 2023-11-01. Last modified 2026-08-11.