A vulnerability in the software image verification functionality of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches could allow an unauthenticated, physical attacker to execute unsigned code at system boot time. This vulnerability is due to an improper check in the code function that manages the verification of the digital signatures of system image files during the initial boot process. An attacker could exploit this vulnerability by loading unsigned software on an affected device.

A successful exploit could allow the attacker to boot a malicious software image or execute unsigned code and bypass the image verification check part of the boot process of the affected device. To exploit this vulnerability, the attacker needs either unauthenticated physical access to the device or privileged access to the root shell on the device. Note: In Cisco IOS XE Software releases 16.11.1 and later, root shell access is protected by the Consent Token mechanism.

However, an attacker with level-15 privileges could easily downgrade the Cisco IOS XE Software running on a device to a release where root shell access is more readily available.