Actually, it's the Intel Converged Security and Manageability Engine (CSME), one component of which is the Management Engine. Researchers from Positive Technologies managed to gain access to 2 of the 4 cryptographic keys protecting various parts of this system.
The result: the ability to read and freely modify files on the CSME's internal storage space. In addition, the second key is used to encrypt the Intel AMT password.
Intel has already released corrections. More details here.