A vulnerability in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker to execute arbitrary commands with root privileges on the underlying operating system of an affected device. The vulnerability is due to improper input sanitization. An attacker who has valid administrative access to an affected device could exploit this vulnerability by supplying a crafted input parameter on a form in the web UI and then submitting that form. A successful exploit could allow the attacker to execute arbitrary commands with root privileges on the device, which could lead to complete system compromise.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-web-cmdinj4-S2TmH7GA