A vulnerability in the upgrade mechanism of Cisco Unified Communications Manager based on the Cisco Voice Operating System software platform could allow an unauthenticated, remote attacker to gain unauthorized, elevated access to an affected device.
The vulnerability occurs when a refresh upgrade or Prime Collaboration Deployment (PCD) migration is performed on an affected device. When a refresh upgrade or PCD migration is completed successfully, an engineering flag remains enabled and could allow root access to the device with a known password.
An attacker who can access an affected device over SFTP while it is in a vulnerable state could gain root access to the device. This access could allow the attacker to compromise the affected system completely.