A vulnerability has been identified in CP 1604 (All versions), CP 1616 (All versions). An attacker with network access to port 23/tcp could extract internal communication data or cause a Denial-of-Service condition. Successful exploitation requires network access to a vulnerable device. At the time of advisory publication no public exploitation of this vulnerability was known.
https://cert-portal.siemens.com/productcert/pdf/ssa-559174.pdf