vulnerability
Cisco ASA: CVE-2023-20042: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software AnyConnect SSL/TLS VPN Denial of Service Vulnerability
Severity | CVSS | Published | Added | Modified |
---|---|---|---|---|
5 | (AV:N/AC:H/Au:N/C:N/I:N/A:C) | Nov 1, 2023 | Nov 8, 2023 | Mar 27, 2025 |
Description
A vulnerability in the AnyConnect SSL 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 an implementation error within the SSL/TLS session handling process that can prevent the release of a session handler under specific conditions. An attacker could exploit this vulnerability by sending crafted SSL/TLS traffic to an affected device, increasing the probability of session handler leaks. A successful exploit could allow the attacker to eventually deplete the available session handler pool, preventing new sessions from being established and causing a DoS condition.
Solution

Explore Exposure Command
Confidently identify and prioritize exposures from endpoint to cloud with full attack surface visibility and threat-aware risk context.