Specially crafted PROFINET DCP packets sent on a local Ethernet segment (Layer 2) to an affected product could cause a denial of service condition of that product. Human interaction is required to recover the system. PROFIBUS interfaces are not affected.
https://www.siemens.com/cert/pool/cert/siemens_security_advisory_ssa-293562.pdf
https://cert-portal.siemens.com/productcert/pdf/ssa-293562.pdf
https://cert-portal.siemens.com/productcert/html/ssa-293562.html