A vulnerability in the web framework of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a buffer overflow condition on an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to the affected software improperly parsing malformed HTTP packets that are destined to a device. An attacker could exploit this vulnerability by sending a malformed HTTP packet to an affected device for processing. A successful exploit could allow the attacker to cause a buffer overflow condition on the affected device, resulting in a DoS condition.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180926-webdos
https://ics-cert.us-cert.gov/advisories/ICSA-19-094-03