An organization is using Android mobile devices but does not use MDM services.

The risk present in an organization using Android mobile devices without Mobile Device Management (MDM) services is that unsigned applications can be installed. Without MDM, there are fewer controls over the installation of applications, which increases the risk of installing malicious or unauthorized applications. MDM services typically provide a way to enforce application signing policies, preventing the installation of unsigned apps.

References:

OWASP Mobile Security Project

NIST Mobile Device Management Guide