A vulnerability in the ROM Monitor (ROMMON) of Cisco IOS XE Software for Cisco Catalyst IE3200, IE3300, and IE3400 Rugged Series Switches, Cisco Catalyst IE3400 Heavy Duty Series Switches, and Cisco Embedded Services 3300 Series Switches could allow an unauthenticated, physical attacker to execute unsigned code at system boot time. This vulnerability is due to incorrect validations of specific function arguments passed to a boot script when specific ROMMON variables are set. An attacker could exploit this vulnerability by setting malicious values for a specific ROMMON variable. A successful exploit could allow the attacker to execute unsigned code and bypass the image verification check during the secure boot process of an affected device. To exploit this vulnerability, the attacker would need to have unauthenticated, physical access to the device or obtain privileged access to the root shell on the device.