CVE-2024-20331: Cisco Adaptive Security Appliance Software

Medium severity, CVSS 5.9. EPSS: 0.7% chance of exploitation in the next 30 days.

A vulnerability in the session authentication functionality of the Remote Access SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to prevent users from authenticating. This vulnerability is due to insufficient entropy in the authentication process. An attacker could exploit this vulnerability by determining the handle of an authenticating user and using it to terminate their authentication session. A successful exploit could allow the attacker to force a user to restart the authentication process, preventing a legitimate user from establishing remote access VPN sessions.

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 6.2.3.1 only; version 6.2.3.2 only; version 6.2.3.3 only; version 6.2.3.4 only; version 6.2.3.5 only; …

Published 2024-10-23. Last modified 2026-08-11.