A vulnerability in the IPsec driver code of multiple Cisco IOS XE Software platforms and the Cisco ASA 5500-X Series Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to cause the device to reload. The vulnerability is due to improper processing of malformed IPsec Authentication Header (AH) or Encapsulating Security Payload (ESP) packets. An attacker could exploit this vulnerability by sending malformed IPsec packets to be processed by an affected device. An exploit could allow the attacker to cause a reload of the affected device.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180926-ipsec
https://ics-cert.us-cert.gov/advisories/ICSA-19-094-04
http://www.securitytracker.com/id/1041737