A vulnerability in the Smart Install feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of packet data. An attacker could exploit this vulnerability by sending a crafted packet to an affected device on TCP port 4786. Only Smart Install client switches are affected. Cisco devices that are configured as a Smart Install director are not affected by this vulnerability. Cisco Bug IDs: CSCvd40673.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi
https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05
https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04