BACnet ATEC devices are affected by a denial of service vulnerability that could be triggered by an attacker residing in the same BACnet network by sending a specially crafted MSTP message. A power cycle is required to restore the device’s normal operation.
Siemens recommends countermeasures for products where fixes are not, or not yet available.

https://cert-portal.siemens.com/productcert/html/ssa-828116.html