CVE-2025-20252: Cisco Adaptive Security Appliance ASA Software

Medium severity, CVSS 5.8. EPSS: 0.4% chance of exploitation in the next 30 days.

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition. This vulnerability is due to improper parsing of IKEv2 packets. An attacker could exploit this vulnerability by sending a continuous stream of crafted IKEv2 packets to an affected device. A successful exploit could allow the attacker to partially exhaust system memory, causing system instability like being unable to establish new IKEv2 VPN sessions. A manual reboot of the device is required to recover from this condition.

Affected products

• Cisco Cisco Adaptive Security Appliance ASA Software: version 9.8.4.15 only; version 9.8.4.17 only; version 9.8.4.25 only; version 9.8.4.20 only; version 9.8.4.22 only; version 9.8.4.26 only; …
• Cisco Cisco Firepower Threat Defense Software: version 6.2.3.16 only; version 6.2.3.17 only; version 6.2.3.18 only; version 6.6.0 only; version 6.6.0.1 only; version 6.6.1 only; …

Published 2025-08-14. Last modified 2026-06-17.