A vulnerability has been identified in SIMATIC CP 1604 (All versions), SIMATIC CP 1616 (All versions), SIMATIC CP 1623 (All versions), SIMATIC CP 1626 (All versions), SIMATIC CP 1628 (All versions). Affected devices insufficiently control continuous mapping of direct memory access (DMA) requests. This could allow local attackers with administrative privileges to cause a denial of service situation on the host. A physical power cycle is required to get the system working again.
https://cert-portal.siemens.com/productcert/pdf/ssa-784849.pdf