When Beckhoff TwinCAT is configured to use the Profinet driver, a denial of service of the controller could be reached by sending a malformed UDP packet to the device. This issue affects TwinCAT 2 version 2304 (and prior) and TwinCAT 3.1 version 4204.0 (and prior).
https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2019-007.pdf