A vulnerability in the Internet Key Exchange version 1 (IKEv1) implementation of Cisco IOS XE Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The attacker must have valid IKEv1 VPN credentials to exploit this vulnerability. This vulnerability is due to improper validation of IKEv1 phase 2 parameters before the IPsec security association creation request is handed off to the hardware cryptographic accelerator of an affected device. An attacker could exploit this vulnerability by sending crafted IKEv1 messages to the affected device. A successful exploit could allow the attacker to cause the device to reload.